[PShabi]

I know Brian didn't specify 6-max, but

If you're playing 6-max, this will cost you bets at best and at worst cost you big pots.

If I'm on the button and you've shown that you can raise hands like A10, K10, KJ, QJ or small pairs up front (which good players do in this game) I'll 3-bet preflop with AK, AQ, AJ, KQ, 88, and 77 all of which you're beating.

If you bet your 99 into me on the flop, I'd raise you with the 77 & 88 on this flop for sure. If you've shown that you'll be passive with strong holdings (which 99 is on this flop) I'll have no problem raising AK, AQ, or KQ here for a free card on the turn. You'll probably give it to me and that's where you start losing pots when you're caught up with "saving bets."

I play very aggressively and I admit there are times when I can be too aggressive. This isn't one of this times though.