Playing Agressively

[Talking Poker]

This is a very general question, so it's going to be difficult for people to respond to.... but simply put:

If you are check raised and you choose to reraise with middle pair, you are bluffing. There is a time and a place for bluffing, of course, but generally speaking, it's not following a check raise, unless you are very certain you can make your opponent lay his hand down.

Selective aggression = good.
Playing like a lunatic = bad.