"Why would you make your own when you can just get one for like $30 online?"

One of the single most disheartening things I've heard from a peer.

Seriously, are you really so incompetent and dependent upon other people's work that you can't even come up with a single reason why I would do this?! Don't you dare try to call yourself an engineer. Call yourself a cheat, cause that's the only way you passed that class.

Even after explaining that making it yourself is one of the best ways to learn about/understand it, they still couldn't understand.