Honestly, people don't really mess with me. They dislike me, yes, and are bold enough to voice it, but that's it.
I've realized that I'm more likely to ignore people than to bother standing up against them. I often just don't care what they say to me haha. I occasionally help people if they're being picked on, though.
A friend of mine has quite a temper, though, and occasionally goes after me if I anger him, even over something stupid. So fighting back is really the only thing I have to do that comes near "standing up for myself", for the most part. It isn't exactly a serious thing to me, though. Something about having someone (who is oddly strong for his size) full out tackle me, then having him pinned by his throat in under a minute is enjoyable.
Both of Dipu's stories made me laugh.