[Borys313]

Imagine one player raised the rest folded, and you sit there with A356 on the button.
You have to raise and its a must, many people will just call but thats wrong.

Imagine the blinds sit there with hands like 679J and similar, if one of them decides to call he will you usually have the best equity of you all!!! When the flop comes low you will start battling with the preflop raiser just to get quartered by the guy who is blinds. He will also hit the flop but from the better side and always make bigger 2 pair then you and higher straights with a hand like 5678.

And thats what you have to avoid, make him fold at any cost.
Not to mention the fact that if you make the pots heads-up you can usually take it down by betting on bad flops cause some will give you credit for AAxx.