Walter Montego: And what about luck? I get real lucky against some of my opponents and other I just get stomped.

Luck will always play a large part of success in games, matches and sets of matches. It's only when you make those sets large that you can discount the luck, because it will tend to balance out.

In talking about the advantage that a computer's knowledge can give in a given game then it's really a question of how many errors the given player is likely to make. That's a function of their skill level, the familiarity of the game type and the complexity. As you noted, some positions are easy and the move is "standard" or "obvious". The set of standard moves becomes larger the more skill a player has and the value of the computer in those positions diminishes.