Quote Originally Posted by Kitxu
3 choices :
you know he's a serious guy and you put him on a 5 ===> fold
you know he's not serious guy and you put him on little something or nothing ===> re-raise to see his reaction
you don't know who is the guy ===> flat call
And the 4th choice is:

You put him on a range based on his stats/reads/tendencies, and then you either call or fold. 3betting here is definitely the worse action imo. And anyways, you don't do it to "see his reaction".