Some people get into self hosting just because they're interested in the mechanics of it, but many people I think got inducted by the fact that for example, Facebook or snapchat make it so difficult to save your own pictures or migrate to another service, or the possibility that Google is reading all of your emails, etc. Others may have been radicalized by a specific event, such as a service provider closing up business and therefore you lose your data.
For me, it was Spore com. I loved Spore, from the time I got it for my 10th birthday to maybe the age of 16 or 17 I poured hundreds or probably thousands of hours into this game. As I got older I became less invested in the gameplay and more invested in the creative aspect of it. I designed some badass creatures and spaceships that I was really proud of. I had a whole line of Spaceships that all served different roles in my head cannon, with different races of aliens following different themes.
EA/Maxis/whoever runs Spore now purged all of them from spore.com, and now they're gone. Years of my childhood essentially put into a locked box and the key thrown away. For me it was like losing a scrapbook in a fire. What right did they have?
So I ask, What radicalized you?
It's hard to say exactly what motivated me, I knew there was a few things I wanted, and self hosted options kept popping up, so I went that route.
Gitea, I wanted GitHub like interface, but didn't want my stuff uploaded to open internet, like gitlab. I use Gitea to backup thingiverse models, especially when they seem to 404 randomly over time.
Inventree, inventory management for stuff I use in electronic or 3d printed projects.
Jellyfin media streaming along with books
OpenHAB, honestly this stuff seems way over my head, I wanted to use this for a few things, but I know I wanted to log power consumption of my smart plugs I have for my 3d printers. Idk if it's actually working, I think I am using something java related to save the stuff, but I gotta go through the stuff again.