(Insert Console Here). I are so witty.
OT: For me, it's a three way tie!
The Pistol Bayonet (Tired of stabbing people from a distance with bullets?)
Digital Rights Management (I payed for it, it's MINE, ya mingebag.)
The "Loaded Chamber" indicator that some handguns are equipped with. A gun is ALWAYS loaded, especially when you 'know' it's empty. Having a mechanical device (That can fail), pop out and say "Hey, there's a bullet in me" makes people ignore proper gun safety, which is going to get people killed.