Nothing, other than the fact that you guys have provided no proof onto why MW3 sucks.
It's a competition of who kills who first
The campaign is typically short and doesn't last long nor have any replay value
The community (Doesn't really count towards the game itself, but it's still a negative aspect when playing it.)
The price (See: Bobby Kotick)
Bobby Kotick (Satan)
The mapping is extremely small, easy to get a hang of, and requires no thought or skill to master
Health that regenerates extremely quickly (Causes it to be extremely easy)
You mind shutting the forget up now?