In order to be a big winner you have to be capable of making the big laydown when you know you are beat.
We have all been in that situtation on the river when your opponent suddenly bets into you after calling on the other streets. There really is nothing that we beat that he would be doing this with, but we call anyways just to prove to ourselves that we are right.
In order to be a successful player we have to learn to trust our reads. If your read is telling you that you are beat, even with a really big hand, then fold. Calling to prove that your read is correct or being stubborn and not wanting to believe that you got sucked out on will eat into your profits.