Lots of whining about the
Spoiler:
time travel
It's almost like the
Spoiler:
conversations between banner/Hulk and the Ancient One and Banner/Hulk and the rest of the team about time travel and why all the traditional movie interpretations of time travel are irrelevant. They don't actually have to return the stones because the changes they've made at each of the points where they retrieved the stones have already created different bubbles for each stone recovered. Their time travel mechanics are less about getting back to the same "time" in the present as that time will now exist differently for each of them since their retrieving the stones each created a different reality. It's more about making sure they all get back to the same bubble. The only reason they return the stones is out of respect for the fact that it is the best chance for the bubbles in which they retrieved them. Explained by the Ancient One and presumably in reference to the fact that if the stone isn't returned then Strange would be unable to beat Dormammu. Rodgers decision to stay in the past doesn't alter the future because, as Banner states, “If you travel to the past, that past becomes your future and your former present becomes the past which can’t now be changed by your new future".