Do you ever enter contests that require specific knowledge? In what field(s) are you an expert or very knowledgeable? D'ya gamble?

Does winning at gambling require more "lucK' than knowledge? I know poker players have to be good at "reading" their opponents. That people have "tells" of which they may be unaware that "tells" the other players if their hands are good or if they're bluffing. Are you good at reading people? Can you tell when they're lying/bluffing?