When my team (Cowboys) plays, I'll generally watch the full game. I also watch some SNF/MNF/TNF games. But yes, it's fair to say I don't find every part of every game interesting (like commercials, cheesy halftime commentary, endless review of plays that will obviously be upheld/overturned in replay, 2 and 17 draw plays, etc) However, filtering out noise doesn't make me less of a sports fan, any more than reading headlines on HN makes me less of an industry enthusiast.