Button

You pick up Q-T suited on the button. It folds to you six-handed, you raise to three big blinds, and only the blinds are left to call. Say the big blind does. Now you have the last word on every street: the flop checks to you, and you already know what your opponent did before you have to do anything. That information is worth more than your two cards. You can stab at a flop you missed, and you can bluff or barrel off position instead of off hand strength.

That's why the button plays more hands than any seat at the table. A Q-T or a suited connector you'd fold under the gun becomes a raise here, because acting last on every street turns a marginal holding into a profitable one. The edge stacks up street by street: a river check into you says nearly as much as a whole betting line.

Beginners treat the button as a bonus instead of the reason to play the hand at all. They open too tight — the same range they'd use in middle position — and give up the one edge that makes wide, aggressive play work. Or they file the small blind and big blind under "late position too" and open just as loose from there, forgetting both of those seats act before you after the flop, not last. That's the whole point of the button.