[Jensson]

People change due to criticism all the time, it really works. If criticism didn't work we wouldn't have so strong urges to do it, the feeling to criticize others is something we evolved to have.

Criticism might not change people the way you want however, it is like punishment vs rewards, you can change people by punishing them or rewarding them, both works to change people but in different ways and often punishment makes the person resent you so you should do it sparingly.