- As a user, I want to flag a bug to watch later, but I don't want to just subscribe because I subscribe to a lot of bugs.
- Implemented by Phabricator "flags". You can flag a bug or a change and even add a note to yourself (the flag and note are private, afaict) about why you flagged it. It then shows up at eg: http://fab.wmflabs.org/flag/
- As a user, I want to indicate that I really want this bug fixed because it affects me.
- Implemented by Phabricator "tokens"
- The missing use case?