Nothing really. I'm comfortable hosting mail, chat, my passwords and important documents. However:

Hosting personal/important data for other people is a bit intimidating because you kind of guarantee for safety and availability.

And services that are likely to be misused for illegal stuff and would be too bothersome. Otherwise i might host an anonymous spam eating email-forwarder, maybe a tor exit-node and a forum where adults can practise free speech. But that kind of stuff just attracts the wrong kind of idiots.

Mail server, but mostly because deliverability in this day and age is a nightmare. If you're some one off running your own mail server in 2023 be prepared to deal with many headaches around IP reputation.

Aegis. Never use a local-only 2FA app on your phone.

I think someone else already mentioned it, but just to reiterate... Anything for other people who aren't my wife and future kids.

Password manager, file backups, photo backup, whatever.

If something happens to me, or I pass away, wifey has instructions on shutting everything down (probably should write instructions on how to save all the important stuff).

But I don't want to deal with other peoples stuff. I like tinkering with my server and different docker containers, etc. So I don't want someone complaining they can't access their photos because I wanted to try something new. Also, just don't wanna be responsible for storing their photos and important documents.