Some examples:

� Warned DS ahead of time that it�s bedtime after one last book. When it�s time, he tried to hit DH. DH told him to go to bed, and he had a crying fit.
� After telling DS not to suck on his thumb, he tried to hit me. I told him to apologize, and he did and cried.

I just started explain to him afterward why those behaviors are not desirable (e.g. it hurts people's hurting, it hurts people physically, etc). I did ask him why he cry, but he couldn't articulate the reason and just keep reiterate that he cried.