What kind of habits doyour kids pick up from school??

Hi, My son is 3.5 years old and he has started his nursery class. When he first join the class,he is bit shy and so lucky that he did not cry during the first few days,but it took time for him to fully adapt to the new environment. Now he has get used to his school life and of course, he did pick up something Negative from his friends. Not very bad things ,but it will be a bad habit and I always remind him not to repeat again. I noticed that he likes to put his hand in mouth,whereby he never did it before attending the school. So I guess most probably he saw some friends are doing so in school and he learnt from it. It will be a bad habit and not hygiene. So I always told him never put his hand in mouth again,or else, I will put some chilly sauce on his hand. Now, he nevere do it again. Just wondering what negative things that your son learnt from his school? Try to talk to him nicely,but don't scold him in the first place. Give him some rewards when he really change that habit. Need lot of patience to educate well our kids, and never use tough method(beating).