Besides obvious blockable cases online, sometimes I block people when they say something that bothers me in any way or if you're cruel to a friend or negative about something I happen to like, it's how I curate my online experience!!
And I used to use block chains all the time. This being said, I also unblock people pretty frequently, too. It just depends on the offense! Most of the time it isn't really that deep and I get over it pretty quickly. Feel free to ask me to unblock you, I don't bite unless disrespected first