A lot of things piss me off about avengers 3/3.5, but cap going back in time to peggy is up there.
You know what its like? It's literally the male version of titanic, that awful scene where rose dreams her happiest moment is not the life she lived, man she married and family she had, but that one time she banged some dude on a ship, even if he was teen heartthrob Leo de Caprio.
Except here it's worse because not only did it actually happen in the movie, but we know that peggy married another man and had a full life with him, so cap effectively erases that man. Also makes out with his... I guess would-be neice, Sharon Carter? Literally channeling a reverse that futurama episode there...
God I loathe those 2 movies, they're when I personally consider the downfall of the mcu, you can trace it back to them.