I think the main difference between expert versus novice game players in general is intensity. Expert players obviously play more often, so they have more invested in the games. They invest more time, thought, and emotions into their favorite games.
Novice players on the other hand do not play often. They might have favorite games, but they do not invest so much of themselves into it.
Novice players probably do not care as much about the outcome, where expert players more often care a great deal. They play a game for hours trying to beat a high score or beat another player.