What are some of the most stupid things you've done?
I spent ages trying to find why my first Java program didn't work. After asking online, I learned the function was System.out.println, not System.out.printIn . (In my defense, the book's font wasn't that clear).
I turn my phone on silent while in school. Unfortunately, that means I can't do my usual trick of phoning it. One time, I searched for it, then saying "It's loud enough vibrating, I'll ring it anyway." So I put my hand into my pocket, took out the phone, dialled in the number, before realising that that was the phone I was looking for.