Personal anecdotes of successful piracy don't make for an open-source license agreement, otherwise I would be a minor king of open-source.

If a database server's license says “only allowed to use for personal purposes”, it's rather obvious that I can't install it at my work. If a keyboard's license says “you may modify the software only for non-commercial purposes”, it's less clear, but also not apparent why the same interpretation shouldn't apply. Most importantly, copyright law doesn't allow willy-nilly use by default in the case of doubt.

I also changed some behaviour in my GPL editor for personal use once without sharing my changes and also I used that version a few times while writing proprietary commercial code

As the other commenter correctly pointed out, GPL only requires you to share your code if you distribute the compiled binary. And, being a fully FOSS license, GPL doesn't restrict commercial use of programs.

Psst I also changed some behaviour in my GPL editor for personal use once without sharing my changes and also I also used that version a few times while writing proprietary commercial code… Pls don’t tell Stallman

As long as you didn't ship the edited binary of the GPL editor with your proprietary software, you are safe here.