When it responded to Tony's nightmares, almost pounding Pepper into jelly...well...that made the suit a little scary. I loved that scene.
Yep, that was a good one. My favorite moment with the 42 was the double take the suit did when Pepper and Tony were bickering in the basement after she found him remotely controlling the suit. I forget what the setup line was, but for a moment, it was like the suit had its own sense of humor.
Hated and still hate the armour segments flying separately. Don't really like the film but don't hate the 42 itself.
If you liked the Mark 7's suit-up sequence, the individual armor pieces is a natural evolution of that. And my favorite Iron Man figure as a kid was the one with the armor pieces in a briefcase, so it was a nice callback to that (for me). So I like it, but I can appreciate if it doesn't work for other people.