See also
Aggression is built into the basic strategy. If you follow it, you’ll have an attacking style of play.
In poker, if no one ever folded and every hand was a showdown, the best hand would always win. But this isn’t how the game is played. Because of the power of betting, it’s often the case that the hand that would have won is folded at some point.
In his excellent book The Theory of Poker, David Sklansky points out that every time you get your opponent to do something different from what he would have done had he seen your cards, you’ve gained. Aggressive betting and raising often convince your opponent that you have the best hand, which may or may not be true. These tactics increase the chances that your competition will make mistakes. The fact that most confrontations are heads-up, and that your style of play usually forces a decision based on seeing only two cards, makes accurate decision-making especially difficult for your opponents. Undoubtedly, some of the times that your opponent folds, he’ll have a better hand than you. Your aggressive betting drives him out. If he could see your cards, he’d make different decisions, such as calling more frequently. But if he doesn’t, according to Sklansky’s principle, you’ve accomplished your mission.