Don't Look Back in Anger
I've lifted this from a VideoGum post. The Mirror Scare is truly a classic. Medicine cabinets close so quickly so they're great for hiding stuff for jump-scares... even though you really can't use the tactic anymore unless you twist it up or parody it because it's so well-known. (And well-parodied, really.)
Also check out Paul F. Tompkins's hilarious "Sink and the Mirror" bit.