You get back to your apartment in the afternoon and try to unlock it with your pin, but it doesn’t open. A few moments later, your neighbour arrives and you give each other a nod before they try to open their door too, but they can’t open it either. Takes both of you a while, but apparently, your pins got switched. And who is the culprit? Why, your mutual best friend who has been shipping you two together for months now.

[ Possible directions you could go: comedy / romance / friendship / fluff / etc. ]