Ultron really comes off as Tony Stark's wit and sarcasm was freed of any sort of restraint and given its own body to roam around in, even to the point where he snaps off a snarky reply to something Cap says, then cut to Tony inside his suit going "he beat me to it by one second"

Also, Hawkeye. Definitely Hawkeye.

"This is probably a stupid question, but . . ."