Avengers 2 starts off as though Iron Man 3 didn't happen.

At the end of Iron Man 3, the impression I got was definitely that Stark was retiring from the superhero life. It seemed like he was out to blow up all of his suits and robot drones or whatever.

If anything, by Avengers 2 it's like he has way more of them. And if it was the case that he had more suits/drones somewhere else, then blowing all of them up at the end of Iron Man 3 doesn't make any sense.

It would even be okay if they explained it in a short film or deleted scene.

I was definitely disappointed with Iron Man 3--out of all the Marvel movies, it seemed like the one that didn't really move the main Avengers story arc at all. The way Age of Ultron starts off only confirmed that.