Karen Joshua is an excellent Gundam character. She is a tough, mobile suit pilot who was loyal to her team.
It is said that she caused the previous commander (More than one had been sent out to lead their group before.) to suffer from a nervous breakdown that he had to be hospitalized for, so everyone thought that she was very difficult to get along with.
Despite her bad reputation, she turned out to be a very respectable character. She told one guy to grow some balls when he started to whine too much and really whipped whiners in to shape. She was an experienced soldier so she was good at that.
It is not a good idea for teammates to whine all the time. Plus, she ended up getting along with the new commander, Shiro (who grew to be a good commander), even though she did not trust him at first.