We all have that bestie who would do anything for us. You can be sure that if someone proposed to their girlfriend at OUR birthday party, we wouldn't take it lightly, either. A woman took to r/pettyrevenge, sharing an infuriating situation that involved exactly that — ugh, the audacity . Well, rather at her BFF's b-day party. That's actually worse. Don't cheap out on your proposal dude, and never, EVER, steal someone else's thunder when they're celebrating something. That goes for birthday part…