As an adult, what seemingly childish things do you get excited about?
I love bridges. If I see a cool looking bridge, I want to cross it, especially if it goes somewhere that I'm not familiar with. Same with stairs outdoors. They feel like an adventure to me.
Buying and selling computer parts. I know it doesn't sound childish but I don't really make much, it's like 0.01 percent of my salary I get paid as a software developer.
Random people call me, I meet them, they buy some random PC parts and it just feels nice.
I have sold hundreds of PC parts for about 2 years. Customers are polite all the time, I know it is unexpected but that's how it is, I have never had any nasty encounters.
I had fears about them running away, but this also never happened. Regarding defects, there was few occasions where the next day they called me and asked for replacement. Usually I sell SSDs, so out of about 100 of them I got back 5. when I retested them 2 of them was working and I sold them again :D 3 dead SSDs are laying on the shelf, not sure what to do with them...