I enjoy sports much more than I used to, and understand much more than I once did why many other people like it much more than I do. Still I don't really get the degree to which people are emotionally invested in it. I get it some. I quite enjoyed it when my local sporting franchise won the World Series. It's fun, essentially, to attach yourself to a goal and then enjoy when that goal is achieved. Fandom is a communal activity and there's a big social aspect to it. Something matters because you convince yourself that it does, and you get to enjoy the ups and downs that go with it.
But I always maintain a bit of distance. The people who are really into it, whose emotional state depends on the fate of the team they support (and supporter is a better term than fan), and who will, in complete seriousmess, argue the moral superiority of their team.... I admit I don't get them.