For #7, I figured this out in kindergarten- the first time I watched Labyrinth. If she'd just touched the wall and walked for awhile, she'd have found the entrance, and then that silly worm wouldn't have told her to go the wrong way, because he wouldn't have had to tell her anything to begin with.
Military Call signs for spelling without errors (Agent D3)
Life hacks. AWESOME?
How to read if someone is lying to you. I'm glad I'm not an interrogator who has to employ these skills. I prefer to trust people however I can certainly see the benefit in knowing these.