Dr Strange, Age of Ultron, and Antman 2 are all kind of afterthoughts in the overarching storyline so far, but these 3 movies set up phase 4s big-bad quite nicely: Kang. Endgame kind of alluded to it when Stark said "when you mess with time it tends to mess back" as well.
Plus, my balls really stink tonight.
Plus, my balls really stink tonight.