When I was about 14, my twin sister (she's the good twin) had a sudden opportunity to go on a volunteer-holiday-something over some weeks that summer in New Jersey or something.
I was a bit jealous because I wasn't getting away during the summer. I couldn't save money as a kid no matter how hard I tried. I got my allowance and spent it on a chocolate bar. Every week. I babysat and earned a bit more. Spent it. I was that kid. My twin had something in her that could resist short term pain for long term gain. That made me a bit jealous too.
Anyhow she had already signed up for a school trip the following Autumn to go to Montreal for Expo 67. This was a big thing. I hadn't signed up for Expo. I couldn't save.
The first thing she did when she got the New Jersey news was give me her Montreal trip. No strings. Just happy to be able to do it. Really.
That taught me more about sharing than well, anything.