College football is the only sport I really allow myself to spend time on these days, and since I bleed Razorback Red, the most loathsome team in all the universe are the Longhorns of Texas. As a little kid, I think I hated Texas before I even knew where Texas was on a map. Since the demise of the Southwest Conference, I've hated any team coached by Steve Spurrier, since we've never been able to beat him.
With the NFL, I spent many long, cold years hearing the crap about Dallas being "America's Team," watching them win so many games, all the while my beloved Miami Dolphins never could quite make it. Dan Marino is still the greatest quarterback to play the game (well, him and Joe Montana).
College Basketball, I guess other than Texas, I'd have to hate UCLA, because they beat us in 1995 for the championship. I also tend to hate any team that Dick Vitale talks about, although I realize that this is due to the sound of his voice rather than the actual teams themselves.
Baseball? I hate every single baseball team that exists because it is the most boring of sports. I'd rather watch curling.
And in the spirit of your article, although I left some explanation, I'll close with this:
I hate Texas -- THEY STINK!!!