imitating bad behavior
DS1 (5) loves to imitate a friend of his who doesn't always make the best choices. In general, DS has a tendency to imitate other children's behavior, good or bad, but it is bothersome that he always imitates bad behavior when he sees it.
My son is no angel, but he will do things completely out of character. For instance, a couple weeks ago at playgroup, a younger child took his new truck, wouldn't give it back, and broke it. DS was upset, but the other mom was trying to handle it. DS never said a word to the boy other than a quiet "it's mine." He was upset but did not lash out at the boy. Then, his buddy, who is also 5 joins playgroup, and they play together. They made a seesaw with blocks and were having a good time playing. Another younger boy comes over and tries to play but ends up knocking it over. His buddy then yells at the younger boy in a very rude way. DS1 starts yelling at him in the same way. It was total imitation since he didn't react that way when his new truck was broken.
Today, again, DS was playing nicely at playgroup, building stuff and interacting with others in an appropriate way. His friend comes, and starts getting into everything he shouldn't and using things in a dangerous way. DS1 starts to do the exact same thing.
It's getting really frustrating. It's not just this friend. He does a sports class with his younger brother. He listens to his coaches. Until, another sibling pair starts wrestling. He sees it, thinks it hilarious, and starts wrestling his younger brother.
Even when he is not imitating bad behavior, he is laughing at it. He told me he likes all the bad characters in books/tv shows because it's funny the way they act.
I have talked to him about how it is important to always make your own decisions about behavior, but what else can I do?? I am afraid that he is such a follower, and I want to be able to instill in him a sense of self-confidence so that he doesn't need to follow.