[NewUser2006]

As for the common mistakes not existing at the higher levels, this simply is not the case. Even at the highest levels you will find some people who will play with poor "basic" strategy.

However, the poker greats are able to suceed at the highest levels for what I think are two reasons:

1) They are able to read hands better than lower limit people. The way this equates to profit can actually be quantitized. Imagine that you are deciding whether to call a river bet facing 5:1 pot odds, and you think your opponent has a royal flush 5 out of 6 times and the nut low 1 out of 6 times. In this situation, you're indifferent to calling and folding, so there is no profit (or loss) in this decision... you simply have to pick a course of action and it won't matter. But if you are a super-reader, you might be able to decide that your opponent actually has the royal flush only 4 out of 6 times and the nut low 2 out of 6. Now the profitable course of action is clear.

2) Being able to manipulate your opponent into playing poorly. This may be even more important than the first. Hand reading skills are worthless (and possibly detrimental) if your opponent has tricked you into believing that he is a payoff station while he is really a pro, allowing him to make folds or value bets that he normally would not have made.

To summarize, the psychology of poker is as important if not more important than the mathematics of poker.