What is your favorite StackOverflow question?

This answer [1] is my favorite as it resonates with many work/life experiences.

[1] - https://security.stackexchange.com/questions/33470/what-tech...

I like the graphic examples in this question (besides the obvious attempts at answers): https://stackoverflow.com/questions/1050222/what-is-the-diff...

At first look I tougth it was brainfuck but it's valid JavaScript:

https://stackoverflow.com/questions/7202157/why-does-return-...

You can't parse [X]HTML with regex. Because HTML can't be parsed by regex.

https://stackoverflow.com/questions/1732348/regex-match-open...