When was the last time someone completely fooled you about something?

I wasn't the one that was fooled but helped fool someone in school yesterday. Myself and a couple others had a new student convinced for a few minutes that an aviation mechanic can only use a green screwdriver to tighten and a red screwdriver to loosen. The logic we used was green means good so you know the screw is installedd and red means bad so you know its being removed. He believed us until one of the instructors dimed us out lol