Ear Worm: The opening theme has been known to induce random audience head-bobbing.
He's Just Hiding: Before the release of Resident Evil: Retribution fans speculated that Wesker survived the helicopter mini-nuke at the ending of the movie. This is supported by some eagle-eyed viewers noticing a parachute opening in the distance when one of the characters revealed himself to have survived. Wesker's survival was later confirmed by a press release for Resident Evil: Retribution.
Idiot Ball: The world has been all but destroyed with a tiny population of still living humans remaining and UMBRELLA is still pissing about with bio-organic weaponry.
Claire backing away from the Executioner looks like she's breakdancing
Take That, Scrappy!: Alice gets brought down to normal, ends up on the receiving end of a Curb-Stomp Battle and has all her clones wiped out. For many, it was considered to be the best thing that the directors did to try and redeem the films. But since Alice still is the only character to actually do anything in this film it's ultimately kind of a moot point.