SPOILERS FOR IRON MAN AND BASICALLY MOST MARVEL MOVIES
Tony Stark is not a superhero. At least not in the conventional sense. Rewatching the original Iron Man what stood out to me the most was how unheroic he is. When comparing him to, say, Spider-Man, you notice that Tony never really does anything out of altruism. The movie is about him becoming a better person, but he doesn't save anybody or fight crime. The only real heroics he does is when he saves a small village from the 10 Rings, but that's not done because he just wanted to save people. It was done out of revenge and clearing Tony's own conscience (the weapons used in the attack were built by Stark Industries). Spider-Man will sacrifice his scholarship, job, and identity to go save some folks (in Spider-Man 2 he literally does this, taking a detour from delivering pizzas to stop some robbers), but to Iron Man, saving people is an incidental plus to his own goals. The Tony Stark from Iron Man would never sacrifice himself just to help others.
The Avengers, however, is a different story. Tony is probably the primary protagonist of that film and the only hero to be changed by his experiences. He starts out the same as he was in Iron Man, but due to a dead Coulson, a missile, and a wormhole, he discovers his heroic side, the part of him willing to make the ultimate sacrifice. It's an interesting build, as most superhero movies would have established that fact before the end credits of their first outing, while it took 3 movies to do so with Iron Man. As I've mentioned before, major Hollywood franchises are becoming more like television in how they are built. You can really consider all the Marvel movies, starting with Iron Man and going up to The Avengers, as Season 1. They introduce everybody with their own movies before throwing them all together for the big season finale. With this in mind, Iron Man 3 is supposedly the beginning of Season 2.
The problem is that Iron Man 3 clearly doesn't want to be this. It wants to be a stand alone movie, not part of a greater whole. But because the Marvel universe is now established it can't be, it needs to be a component of this world. This may explain why the movie feels so disorienting, and why even though it's certainly not a bad movie by any means it's definitely disappointing.
