My main problem is that most of the stuff we learn after 8th grade has no practical use.

Just the other day I used the Pythagorean theorem to prove that the iPad 3 did not meet the pixel density requirement to be considered to have a retina display, and then went on to use trigonometry to prove that pixels per inch and arcseconds per pixel were directly related. All to my pleasure and the dismay of apple [censored]

Edit: Wow, that's completely censored now? Now it looks like I'm swearing them out
