2 - you spend time looking at house hold products trying to devise a method for improvement.
3 - you actually buy technical books.
4 - you think that your way is the best way to do everything and constantly challenge ideas.
5 - you solder tools together to form new objects.
6 - you constantly inform people that the ships in Star Wars should all be silent in space.
7 - ...and pick out other faults in movies regarding machines.
8 - you tell people that time travel is impossible.
9 - ...minutes later you think of how you would build a time machine.
10 - you know "natural frequency" has nothing to do with bowel movements.
11 - you get angry when people won't let you fix things they've broken.
12 - you tried to build Transformer toys out of lego as a kid.
13 - ...and tried to invent various lego contraptions in the hope of making money.
14 - you beg everyone you know to call you "Scotty."
15 - you can do vector calculus in your head, but you forgot how to do long division.
16 - you consider a databook "good reading" when you're on the toilet.
17 - the first thing you do with anything new is take it apart to see how it works.
18 - the last time you moved, you needed two dumpsters to haul off the scrap electrical parts from your work room.
19 - you not only know what a left-handed constabulator is, but you designed one once, for fun.
20 - you paid more for math and science books during college than most people pay for tuition.