The most useful tools your parents never had.

My dad and I are both tool-guys and I can't think of anything that I own that he doesn't. But there is one thing I taught him. The mindset of "everything is just nuts and bolts". I always try and do vehicle maintenance myself. He watched me change brakes, swap suspension parts, change an axle. And he asked me the one day where I learned how to do that. And my answer was 2 things. A: YouTube of course haha and B: it's just nuts and bolts.