Falsehoods Programmers Believe

This isn't because programmers are especially likely to be more wrong than anyone else, it's just that programming offers a better opportunity than most people get to find out how incomplete their model of the world is.

The classic (and I think the first) was about names.

There have been a few more lists created since then.

Time. And time zones. Crowd-sourced time errors.

Addresses.

Possibly more about addresses. I haven't compared the lists.

Gender. This is so short I assume it's seriously incomplete.

Networks. Weirdly, there is no list of falsehoods programmers believe about html (or at least a fast search didn't turn anything up). Don't trust the words in the url.

Distributed computing

Build systems.

Poem about character conversion.

I got started on the subject because of this about testing your code, which was posted by andrewducker.