Because they’re following a team in a league and they’re interested in the scores of competing clubs, so they know the chances of their team a title etc. It’s not unusual during tight title competitions to be watching your team play some crucial game.. and everyone explodes in joy in the stadium, because some other team playing another game in another city lost.

* Also betting

* also oddball interesting games that you may not have the time to watch

* also once upon a time this is how you followed sports, you maybe saw 1-2 games a week and the rest was in the newspaper.