One of the most effective ways to approach the game of poker is by using selective aggression. this is nothing new, and has been proven time and time again by those who have the ability to implement it in it's best application. It involves knowing when to push hard with hands, whether you have a strong hand, or you have a read on the others in the pot that tell you that they will lay down to a proper sized bet. The hardest part about the strategy, IMHO, is the fact that it limits your hand selection more than playing tight. You really need to realize that the important part of selective aggression is the SELECTIVE.

This will force you to lay many hands down, and create a solid/tight table image. Unless of course you're playing your normal home game and everybody there plays you all the time, in which case your image is pretty much already set in stone for them. As you are laying down all of these hands, the real trouble starts. After playing 3 hands in 2 hours, you get the "itch" to start splashing around and play more hands. At first, if your image is secure, you may pick up a few pots with early action. However, eventually you'll run into a player that picked up a hand and get played back at when you have a weaker hand than you should be playing. So imagine that you've been playing very selective hands for the past 5 hours, and you're building your stack slowly. Then you get the urge to play a hand out of boredome, and not because it fits into your stategy. Something like this might happen.
NLH tourney and you're in MP with QJo
You make a standard raise of 3x
You get a caller from the button, and think he probably has a hand, but with position it opens his range quite a bit.
Pot is 7.5 bb
FLOP = 7s 8h Ad
You decide to take a stab and bet about 5bb
Now the button calls again, and you decide that he's probably hit his A and you need to slow down.
TURN = 2c
Not a scare card, but you're done with this hand and you check to the A on the button.
The button checks behind you. Maybe he called with 9-10 or 10-J??
RIVER = 6c
Now you've put yourself in a position where you have to make a hard decision. If you bet here, and the button has an A, you'll probably get called. If the button had 9-10, he's holding the nuts and you'll get raised. You decide to check, and protect your stack. The button checks behind and waits to see your cards. You now get to make the biggest mistake of the hand, showing your hand to a table that was convinced you were only playing monsters. you show your QJo and whether you win that pot or not, the damage is done. You are no longer going to get erspect with your raises. You have just spent 5 hours creating an image that was blown out of the water with one misplayed hand.

How's your EV on the time you invested now?

Interesting... I think anyone who would notice, would understand getting 'frisky" and even the c-bet. Table image is still protected to those folks.

The majority of casual players, probably play QJo anyway and won't think much of it....