Maybe it's the fact that the system has continuously failed to demonstrate how is it possible to apply more complex math (trigonometry, analytic geometry, calculus) in real life situations or the way it can even be useful.
Personally, I've had problems with math because I tend to suddenly lose interest and I just get lost in the topics.
I find it extremely disgusting when it comes to direct family. On the other hand, many of you think it would be incest if it's with your second cousin; as far as I'm concerned that's not considered incest. It's quite common in my family to marry second/third cousins, as a matter of fact, my grandparents on my dad's side are SC's, maybe that's why I don't see it as taboo.