Do you think that Curley has aggression towards others because he is small and he is trying to get over his insecurities?do we see any examples in book
Boys are notoriously cruel and aggressive. A boy who happens to be exceptionally small will inevitably get taunted and pushed around in the schoolyard for year after year. During that time he may build up a lasting hatred for all other males and at the same time resolve to develop his muscles and learn to be a good fighter. Even so, he will always have an inferiority complex because of his small size and the abuse he has received from bigger, stronger males. This would explain why Curley has acquired the physique of a body builder, why he became an amateur boxer, and why he has such a pugnacious character.
The boys may not realize it, but all of their aggressiveness results from the age-old mating competition. There too Curley would have been at a disadvantage as an adolescent because the bigger boys would typically have been more successful with the girls. It is logical and plausible that Curley might have ended up marrying a girl who was only about sixteen years old. He could have felt inadequate with an older woman, and it appears that he felt some inadequacy even with the teenager he married.
Yes. Although we never get an actual insight into Curley's mind to explain precisely why he acts so aggressively,this is a likely reason. Old Candy hints as much to George and Lennie when they first arrive at the ranch, and we see an instant example of this when Curley starts picking on Lennie almost the moment that he lays eyes on him. Lennie's huge stature and simple-mindedness arouses his scorn. He doesn't seem to get on well with any of the other men at the ranch either, who generally look down on him. He doesn't have a close relationship with his wife either. So he evidently feels he has to square up to other people all the time, and challenge them physically as well as verbally (he is an amateur boxer). The fact that he is the boss's son also no doubt encourages him to go around picking on other people, certainly the ones that he feels he can dominate, like Lennie, although he comes off worst in the fight with Lennie.