It's important for Dads to laugh with children - not AT them. Deliberately embarrassing children with redicule or criticism can destroy their self esteem, and possibly build a resistance between them and you. This is a balancing act. Everyone should learn how to handle criticism and redicule, but it should be taught to your children in measured, positive doses to educate and build rather than destroy.
Don't belittle children. They may be little but they still deserve respect and proper treatment. Kids often take comments more personally then they let on. You may think that what you are saying is having no effect. However, their external calm or diffidence can be hiding a tornado of emotions, including deep pain.