I paid for a dedicated server with an unmetered 100mbit connection back in the day. (More than a decade ago, now that I think about it) I wasn't using it for much, so I decided to be a good citizen and run a Tor exit node on it. No filters, every port, why not? What could go wrong?

Well, it turns out you can run bittorrent over Tor. Got dozens of DMCA emails, host took the server down within 24 hours. Taught me a lesson on being nice.