When I was 19, I visited my dad in San Fransisco. My step-brother flew up from LA in a RG Cessna. Watched him land at San Jose, then we jumped in for a low level loops around San Fran (probably can't do that anymore) then landed over at Half Moon Bay. Jumped out, had a coffee, then back in for the return flight to San Jose. Then we watched a few aircraft doing circuits for a while. I was fascinated by it all, and was amazed when the brother in law told me that some of the pilots were practising glide approaches. Always thought aircraft would fall out of the sky without engine power. The seed had been planted, but study (and hence no money) meant I couldn't do anything about it for several years.
What turned out to be many years later, the wife bought me the book QF32. Strangely enough it got me really excited about learning to fly. Now have my certificate and am loving flying, just don't get to do it often enough.