The Threat is stronger than the execution.

"The threat is stronger than the execution"-Aron Nimzowitsch

Imagine playing a game and everything is going fine, and then your opponent makes a move that doesn't necessarily win the game with just that move but starts a chain reaction that ends in a gain of material or mate?  I play a lot of games where my opponent will do a pin, and I will say, "Bah, everyone does that," and I sometimes dismiss a very powerful move as an easily solvable move, however, sometimes, there is something to the innocuous pin that you think achieves nothing.

Notice in the game I didn't bother to check my own candidate moves and opponent replies to them, I just picked the first move that came to my mind and made it without checking my answers.  Then later, I got into a predicament where I could have saved the immediate loss of material by moving my king to f1, breaking the pin, but I tried to hold onto a lost position without giving up the right to castle.  My first blunder was moving my knight to attack his queen.  I may have lost a pawn, but at least I wouldn't have lost a piece, had I of just castled, instead of attacking the queen with my knight.  Anyway, I think this game proves Nimzovitches point, that the threat is stronger than the execution.  I can't tell you how many games where I think a threat is a waste of time but end up losing the game because of it.  Checks captures and threats.  Don't underestimate any of them.  The second you do, is the second you lose.