Iron Man 3 ends with Tony Stark destroying all the Iron Man suits and retiring from superhero duty. 2 movies later he's back in the suit like nothing happened and the PTSD isn't brought back until Infinity War.
I recall my father took the family to watch Thor 1 when it first came out but I had no idea the MCU was a thing. A few years later the Avengers was TV, my brother had the remote so I couldn't change the channel, and after watching it my brother said "They have movies for the main characters" and I got curious. Civil War was the first MCU film we watched in the theaters, ever since me, my brother, and my father all have a tradition to go watch MCU movies when they come out.