The revised personality is below; please let me know if I need to change anything else!
Weiss comes off ice-cold to most everyone when she first meets them. There are a few reasons for this - arrogance, even a bit of narcissism - but one reason is underneath the surface. Being the heiress to the largest company in the world has come with a need to keep people at a distance. Why? The company has had a target on its back from the moment her grandfather started it. It's been a full-out war, resulting in near-constant bloodshed: family friends have disappeared, board members have been executed. Keeping people at a distance is a defense mechanism - if people aren't close, it doesn't hurt as much when they die.
For Weiss personally, this conflict has a more painful side: her father is angry every time he comes home, and he takes it out on his daughters. (As a note, Weiss doesn’t put it in so many words; she says she had a ‘difficult childhood’, related to her father’s anger.) Growing up in that kind of setting has influenced her personality a lot - trying to stay on the good side of someone that's angry will do that to a person. What does this mean? Weiss is a perfectionist to a fault; she’s trained until her fighting style is almost like an elegant dance, she’s incredibly smart, and she works hard. Of course, it’s not all work for her. she admits that while things weren't easy, she’s had almost everything she wants given to her.
By the time we first meet her in the series, she not only has an attitude of ‘well, of course I deserve to be at the top’, it’s combined with a defensive ‘and everyone else around me is a dunce’. It's shown most dramatically when she first meets Ruby Rose. Ruby is disoriented and bumps into Weiss' luggage, and Weiss overreacts - first lecturing her (because her luggage contains a large amount of Dust) and then outright yelling at her after Ruby sneezes and causes an explosion.
This attitude doesn't apply to people that Weiss perceives as being on her same level - if not in terms of intelligence, in terms of fighting ability. This is shown explicitly when Weiss approaches Pyrrha Nikos about being on her team; Weiss knows Pyrrha's fighting skills (presumably due to the fact that Pyrrha has won a tournament for the past few years) and flat-out sucks up to her.
Weiss describes herself at one point as 'difficult', after pairing up with Ruby and immediately finding herself butting heads with the other girl. She prefers to stick to a game plan and a strict set of rules, while Ruby is a lot more spontaneous. It seems like they're going to be at odds forever, but Weiss is the one that breaks the standoff - it's with a lecture and an eyeroll, but she manages it.
Despite her 'difficult' personality, when it comes down to it, Weiss can work with other people. It's shown first in the fight with the Giant Nevermore - if there's a plan in place, she's able to put her own reservations aside and follow the plan.
Despite this, it's a real shock for Weiss when after everything, she isn't named team leader. This is enough to drive Weiss to outright anger: yes, her teammates are cheering for her, but if she was the leader, they’d be in a lot better shape. It's a matter of seeing herself as 'better' - she's worked hard, she's studied, she's trained, and she deserves it. She talks to one of her professors about it, but she doesn’t get the confirmation that she would have been the better leader. Instead, she’s told not to focus on what she doesn’t have, but instead focus on being the best person she can be.
That conversation sparks a change in Weiss. She acts more open towards people, she’s bonding with the team, and she’s smiling a lot more. (As noted when the preparations for the Vytal Festival begin, the smiling is almost creepy because of how out-of-character it seems to be.) It's not an easy change for her to make, though, and that's painfully clear when Weiss talks about the White Fang. She's been brought up to see most Faunus (people with animal features) as criminals and taught that she's above them - to the point of calling them 'riffraff'.
What does it get to make the change stick? The revelation that her teammate Blake is not only a Faunus, but a former member of the White Fang. Blake goes missing after accidentally letting her past slip, and the twelve hours Weiss gets to think about what she's said and done lead her to a conclusion: she's going to do her best to put those bad attitudes behind her.
By the time we see Weiss again in season 2, she's managed to make those changes stick. She becomes more willing, if not more able, to check her own perfectionism and snark in favor of what's best for everyone. She's seen relaxing with her teammates and even laughing with them. She's also a lot more willing to call people out when they aren't keeping up with an agreement or a promise - as seen when she calls Blake out on acting 'moody, antisocial, and quiet' after her teammate specifically promised to come to them with any problems.
Those changes aren't always visible, though. Weiss puts the cold facade back on when she needs to do something that's difficult or unpleasant. This is made painfully clear when Weiss calls her family's company to get them to release some documents - she visibly tenses when she makes the call. When asked whether she wants to speak to her father or her sister, she says no a little too quickly. It's clear she still has a way to go with making changes in herself, but she's a lot more willing to try now than she was in the earliest episodes.
Re: REVISION REQUESTED
Weiss comes off ice-cold to most everyone when she first meets them. There are a few reasons for this - arrogance, even a bit of narcissism - but one reason is underneath the surface. Being the heiress to the largest company in the world has come with a need to keep people at a distance. Why? The company has had a target on its back from the moment her grandfather started it. It's been a full-out war, resulting in near-constant bloodshed: family friends have disappeared, board members have been executed. Keeping people at a distance is a defense mechanism - if people aren't close, it doesn't hurt as much when they die.
For Weiss personally, this conflict has a more painful side: her father is angry every time he comes home, and he takes it out on his daughters. (As a note, Weiss doesn’t put it in so many words; she says she had a ‘difficult childhood’, related to her father’s anger.) Growing up in that kind of setting has influenced her personality a lot - trying to stay on the good side of someone that's angry will do that to a person. What does this mean? Weiss is a perfectionist to a fault; she’s trained until her fighting style is almost like an elegant dance, she’s incredibly smart, and she works hard. Of course, it’s not all work for her. she admits that while things weren't easy, she’s had almost everything she wants given to her.
By the time we first meet her in the series, she not only has an attitude of ‘well, of course I deserve to be at the top’, it’s combined with a defensive ‘and everyone else around me is a dunce’. It's shown most dramatically when she first meets Ruby Rose. Ruby is disoriented and bumps into Weiss' luggage, and Weiss overreacts - first lecturing her (because her luggage contains a large amount of Dust) and then outright yelling at her after Ruby sneezes and causes an explosion.
This attitude doesn't apply to people that Weiss perceives as being on her same level - if not in terms of intelligence, in terms of fighting ability. This is shown explicitly when Weiss approaches Pyrrha Nikos about being on her team; Weiss knows Pyrrha's fighting skills (presumably due to the fact that Pyrrha has won a tournament for the past few years) and flat-out sucks up to her.
Weiss describes herself at one point as 'difficult', after pairing up with Ruby and immediately finding herself butting heads with the other girl. She prefers to stick to a game plan and a strict set of rules, while Ruby is a lot more spontaneous. It seems like they're going to be at odds forever, but Weiss is the one that breaks the standoff - it's with a lecture and an eyeroll, but she manages it.
Despite her 'difficult' personality, when it comes down to it, Weiss can work with other people. It's shown first in the fight with the Giant Nevermore - if there's a plan in place, she's able to put her own reservations aside and follow the plan.
Despite this, it's a real shock for Weiss when after everything, she isn't named team leader. This is enough to drive Weiss to outright anger: yes, her teammates are cheering for her, but if she was the leader, they’d be in a lot better shape. It's a matter of seeing herself as 'better' - she's worked hard, she's studied, she's trained, and she deserves it. She talks to one of her professors about it, but she doesn’t get the confirmation that she would have been the better leader. Instead, she’s told not to focus on what she doesn’t have, but instead focus on being the best person she can be.
That conversation sparks a change in Weiss. She acts more open towards people, she’s bonding with the team, and she’s smiling a lot more. (As noted when the preparations for the Vytal Festival begin, the smiling is almost creepy because of how out-of-character it seems to be.) It's not an easy change for her to make, though, and that's painfully clear when Weiss talks about the White Fang. She's been brought up to see most Faunus (people with animal features) as criminals and taught that she's above them - to the point of calling them 'riffraff'.
What does it get to make the change stick? The revelation that her teammate Blake is not only a Faunus, but a former member of the White Fang. Blake goes missing after accidentally letting her past slip, and the twelve hours Weiss gets to think about what she's said and done lead her to a conclusion: she's going to do her best to put those bad attitudes behind her.
By the time we see Weiss again in season 2, she's managed to make those changes stick. She becomes more willing, if not more able, to check her own perfectionism and snark in favor of what's best for everyone. She's seen relaxing with her teammates and even laughing with them. She's also a lot more willing to call people out when they aren't keeping up with an agreement or a promise - as seen when she calls Blake out on acting 'moody, antisocial, and quiet' after her teammate specifically promised to come to them with any problems.
Those changes aren't always visible, though. Weiss puts the cold facade back on when she needs to do something that's difficult or unpleasant. This is made painfully clear when Weiss calls her family's company to get them to release some documents - she visibly tenses when she makes the call. When asked whether she wants to speak to her father or her sister, she says no a little too quickly. It's clear she still has a way to go with making changes in herself, but she's a lot more willing to try now than she was in the earliest episodes.