[lengthy]

yes. but I will try to give an explantion.
aggressive poker is winning poker. limp calling with a hand like 33 is a weak play because unless you hit your set your forefitting your hand to the person that had shown the real strengthy. when a majority of the times 33 is the best hand but can't call a bet because you have an underpair.

ill try to take two scenarios to demonstrate.

lets say you are in second to act and are dealt 33. you limp and the button raises with KQs. everyone else fold and you call. obviously you don't know his hand. anyways.
flop:
A 7 2
you check, he bets, you fold.
you lose with the better hand.

second scenario.
you raise 33 second to act, get called on the button by KQs. flop comes
A 7 2
First off, its not a good flop for your hand but its an even worse flop for his hand. you make a standard c-bet and he folds. you win.
if he calls you get can easily check fold the rest of the hand unless you hit your two outer.
there are some great articles about c-betting and great posts here that will help improve your game.