My obsessions are never small, they are big! My fangame, Sona, Rubik's cubes, Sona, my fangame, AI, programming, Sona, my fangame...
If you mean pet peaves though, I have a few. The first one that comes to mind is the kind of equation you see in ads, like "1+1 = 3" because if you buy two of X you get a third X... I hate it!
Do you often replay the same song again and again?