Not really a case of 'why do I keep playing it', because I don't, but I suck at football games.
Played a fair amount during uni because that's what others enjoyed, but I couldn't get my head around it at all. I couldn't stop focusing on one player. The idea of jumping between controlling different players confused me and I'd always end up trying to score with a defender, or end up running the winger into the sidelines because I was watching the wrong person.
Not sure why I suck so much at this particular type of game, but I do.