goodbye waiter
A person who will publicly announce their intention to leave a place, whether it be in real life or on the internet, but will not actually leave until enough people have said 'bye' to them. Often, they will re-announce their intention of leaving multiple times.
"Man, Chris, is such a goodbye waiter. I don't know why he needs everyone in the place to acknowledge that he's leaving, he must be insecure about something."