I love two things: Comic books, and putting too much thought into organizing fiction. And with those two loves, is it any wonder I have a comprehensive Marvel Cinematic Universe viewing order? No. No, it is not. It should be fairly apparent.
So here's the rules: I'm not doing this timeline by chronological order of MOVIE; any yahoo can do that. No, this is a chronological order of SCENES.
That's right, all those flashbacks are getting placed where they go in time. The exception is narrated flashbacks. So that scene in Ant-Man, where Hank explains what happened to The Wasp? That goes along with the rest of Ant-Man, because it's a story being told in the present. But that opening scene of Iron Man 3 that shows Tony meeting Killian in 1999? Watch that before you watch a single frame of Iron Man.
Also, I didn't even try to include the TV shows, Netflix series, or One-Shots, because I'm not an insane person. If you want to try to fit those into this timeline, good luck. I wish you well.
For now, I'll just give you my fun little viewing order, if you want to line up the whole thing into one horrifically long viewing party. If you do want to watch it, at least break it up into chunks, Jesus.