Also, "define <word for which the definition is obvious>".
If you can't write a mathematical proof of it, it doesn't exist, and any discussion of it will inevitably lead to a bunch of people arguing semantics.
This site is one of my favorites, but when an article about sexism in the industry hits the front page, I do what I can to avoid the comments. The majority of the time, it will be things like
* "I still have a problem with this notion that simply because women may be fun to look at, that they are objects."
* "I don't think you'll ever be able to take the objectification of women out of society, and I don't know if it's necessary to try - we've seen women begin objectifying men in some capacity in the last seventy-five years or so, and I don't know if that's necessarily an unhealthy thing. Better to let that objectification be out in the open than keep it locked up in your head."
* "I really hope that everyone is as equally offended and quick to point out sexism for every advertisement, television show, and movie featuring a very fit, shirtless man doing a stereotypical "masculine" activity"