6. Supergirl
Come on now, there has to be some self-awareness. If at any point during your costume choosing, you realise that your stomach is surprisingly chilly, or that passing people are wondering why your belly button looks so incredibly sad, you should probably reevaluate. Also, someone should probably tell Superman that his backside appears to be on the wrong way round.
5. The Joker
Though Heath Ledger's superlative performance as the Joker in The Dark Knight was a revelation, and a triumph of artistic commitment (with obvious acknowledgement of the subsequently tragic cost,) the more restrained wardrobe choices made it infinitely more possible for cosplayers to recapture the look. All it took was a tie, a wastecoat and a shirt, and while the chap pictured here went as far as getting close to the actual designs of each item, you really can't look past the luminous green spaghetti hairstyle. If you're going to commit, at least commit where it matters - the Joker effectively boils down to a white face, a gruesome scar-smile and green hair, and those are the elements that every cosplayer should be focusing on. Pushing some green paper through a shredder and sprinkling the results onto your head is just not going to cut it.