EYE TEST!
Every human has a blind spot in each of their eyes. Position your face between the X and the I below focusing on the dot between them. Close your right eye and look across your face at the letter I with your left eye. Now move your face back and forth at the screen, at a certain distance the X should vanish somewhere between 30cm away.
_______________X_________________.__________________I
This happens to all animals except squid, so if it doesn't work for you then the only logical conclusion is that you are a squid.
ehem almost forgot
Topic: what other pointless debacles do you know like this?