I think in life, and most people who really know me would concur with this, I tend to be pessimistic. That way when things turn out good, I am happy but if things turned out as I expected, I don't get down. Given my medical condition, its important not to get too down so this attitude works for me.
Now when it comes to my sports, sports to me is entertainment and I like the action and to be happy when I am entertained(hence why I avoid tearjerker movies like the plague). So I am a diehard Celtic, Patriots and Red Sox fan and always try to be optimistic and positive when watching, discussing or thinking about my teams.
I just find it ridiculous to get very angry and negative over a form of entertainment. Don't get me wrong, if something happens that causes my team to lose, I get a little p!ssed, but for like two seconds and then its gone. But what I will never understand are people who love their team but only can be negative and angry when watching or discussing them. They are there to entertain you. If they are making you angry, depressed, negative, aggravated or hostile, perhaps its time to step away from following that team for a while and get a better perspective of why you follow sports.