Your question doesn't make sense onqun. Being aggressive isn't a bad thing. It isn't the same as being loose, or anything like that. Being aggressive just means that you are putting pressure on your opponents with bets/raises, which is generally the best approach because you not only have a chance to win at showdown, but now you have a chance to win immediately if they fold. This doesn't mean go out there and start raising everyone with any two cards, just that if you are calling or limping all the time, instead of raising or betting when you have a hand, then the chances are you will be a consistent loser.

Also play money is gonna be nothing like real money, as far as exploiting players etc. goes.