Does it bother you when other players call you a "Calling Station?" Are you constantly being told that calling is bad? If you listen to the majority of professional poker players, they will tell you that you shouldn't be calling. If the hand you start with is not good enough to raise with, then you should fold it and save yourself the money. While there certainly is a lot truth to that theory, there are times when calling can help you out. Many times calling can lead to big wins when folding costs you money and raising costs you money.
Those same pros that are against calling will tell you to vary your play, that you should switch up your playing styles based on the betting attitude at the table. One of the reasons for this is that very aggressive games can earn you much more money if you know how to take advantage of it, and one of those ways is the call.
Take, for example, a nut flush. If you start out with an Ace Three of spades and someone raises the pot twice the big blind pre flop, should you call? Here is a situation where the answer is yes. Imagine you do, and the flop is two spades and a blank. Once again a bet comes that you can handle; you call. The turn is another spade; you now are unbeatable, as long as the board does not pair (which could make quads and full houses possible.) Once more the bet comes to you; some thing you should move all in at this point. But what if there are a few players in the hand, all just calling? You would scare them all off at this point with a super aggressive move just when the third spade shows up. If you are lucky someone else will bluff at it, or even better, hit a sub nut flush and go all in.
Once the river hits you can go all in and rake up a huge pot, all because you were calling from the beginning.