A close second for me is the people who think they are entitled to your time. So if you block them on social media, or on a forum, or in a chatroom or something they make like 10 accounts to try and get even with you because their feelings are hurt.
What do you think?
Yeah, I feel this part of your story. These are people who don't have control over their emotion. They act immature and can't move on.
They devote all their time to stalk the hell out from someone, such action really gets one annoyed.