In addition to the sibling comment, I'd say that to enjoy the game, you really need to appreciate what's hard, the incredible acrobatic feats the players do, the intricate positional maneuvers, and how much training goes into all that.

But I guess it is hard to do that later in life, if you did not grow up in a football (soccer) culture, maybe playing recreationally as a boy, and avidly following the game.