Cold Calling Raises
Imagine this, you are sitting in middle position, and see KQo in your hand. The action makes its way towards you, fold, fold, raise. Now, it's your turn to act. The decision you are making is whether or not to make a Cold Call. That is, you have nothing invested into the pot, and you would have to pay two or more bets to see the flop.
One of the leaks that exists in many player's games comes from calling raises cold, without having a top notch hand of their own. A call here is especially bad if you have a hand that can be easily dominated by a premium hand.
A raise is an indication that a player has a strong hand. Players raise with hands like AA, KK, QQ, AK, AQ. If you decide to call two bets and enter the pot, you should have a strong hand as well. You've already been clued in on the fact that your opponent has one, and you'd like to start on at least equal ground if you're paying extra to enter the hand.
The problem with calling a raise cold without a premium hand is that you can easily find yourself dominated. While you have a good starting hand with KQ, if a King lands you may only be falling further behind in the hand. If your opponent is raising with a quailty hand like AK, he will have you outkicked at the end. And on the turn and the river, you'd be drawing pretty thin. Even another King wouldn't help you. This is a bad situation, and one you want to avoid.
One of the things that makes this an expensive mistake is that it is hard to leave these hands go, and you'll often play them (betting or calling along the way) to the river. After all, you've landed your top pair with a solid kicker. If you bet just once at each stop, you will have put in 2 small bets to see the flop, another after the flop, and a big bet on the turn and the river. That's 3.5 big bets, or $21 at a $3/6 table.
If you do call with a less than premium hand, say AJo, and it turns out your opponent was raising with TT, things are better for you. But here's the rub, when you win hands like this, you run the risk of not making as much as you lose when you lose hands like this.
For example, the initial raiser has TT, you call him with your AJo. The flop comes, and you hit your Ace. Several things can happen, but with at least one overcard on the board it is easier for Mr. TT to get away from his hand. If you try to raise him on the flop and he drops, or if he check/folds on the turn he's put less into your pot than you would have put into his. His 2 small bets to see the flop and one small bet after the flop only add up to $9 at a $3/6 table.
In our example, if things go bad you lose $21. If things go good, you win $9, maybe $15 if you can coax another bet out of him. Now it's even easier to see how this is a leak in someone's game. Even when you were able to win as many of these pots as you lose, it's still possible to end up with less chips in your stack at the end.
I'm not saying to never call a raise cold, but I am saying, be aware of this event at the tables. Even though you may have a hand that you would usually make a raise with if you were the first to enter the pot, it may not be good enough to consistently call a raise with.