I do a lot of nmap scanning for fun and out of curiosity. I pick a site and check out what ports they have open on the server behind their domain. Never did any

I do a lot of nmap scanning for fun and out of curiosity. I pick a site and check out what ports they have open on the server behind their domain. Never did any attacks nor do I intend to. I'm asking questions to widen my understanding of how and why I might get in trouble for it.