Nothing quite so annoying and untimely as someone pounding urgently on your door while you're right in the middle of hot sweaty sex. Mental cursing ensues.
Nothing quite so amusing as having said urgent knocker above open the door when your naked boyfriend goes to answer it and has to hide his nakedness from random stranger. Guffaw, guffaw, uproarious laughter!
Honestly, the fact of our anticipated reason for actually pausing and answering the door was a good one, but finding out the neighbor's car had its headlights on was a bit of a reason to be miffed. Piss off, we're busy.
Resume your positions and ... 'Take 2!' ... SNAP!