A person who pisses off everyone around him/her from constantly stressing a certian subject (usally an unpopular opinion) nonstop.
Rebecca: Karen is such a fucking piss boiler
Tina : I know all the time
Karen : (Walks in and starts bitching about how vaccines caused her child's autism).
"Piss on your grave" is what you tell someone when you greatly resent something they have said or done, assuring them that you will not forget it and have no respect for them.