The most important decision you ever make playing Holdem is whether to hold or to fold. You make this decision constantly, and it is the decision that lies at the root of every other decision you make when playing Holdem.
Decisions in poker must be made on the spur of the moment. You have seconds to make a decision that can possibly cost you a large sum of money or win you an even greater sum of money. You have little time to think about what you will do, and you must size up a number of factors before making a decision.