To say that Avengers: Infinity War changed the MCU completely is a bit of an understatement. Not only did it leave the landscape of the franchise's story in tatters thanks to an incredible cliffhanger, but it also fundamentally changed the tone of the entirely cinematic universe.
We'd been fed on mostly family friendly movies - albeit with dark puncutations now and then - with MCU movies wearing their Disney affiliation mostly loud and proud. And then along came Infinity War and clicked that all away along with half of its cast. And even more specifically, it actually retroactively changes a lot of what came before it. Or at least how you'll react to it now as an informed audience.
Now that the dust has settled, going back to watch the rest of the MCU with the knowledge of what happens in Infinity War changes a hell of a lot. Particularly in terms of your perception of some of those scenes...
Back in Guardians Of The Glaxy Vol 2, Rocket was very much the Guardian who most personified James Gunn's message that the sequel was about how the group would BE a family after the first movie thrust them together as one. He was obstinant, resistant to opening up and secretly terrified because of his past and it took for him to be coaxed into accepting the family by Yondu in the end.
Instead of being a fiercely-committed loner, he began to accept that he could belong, even despite the awful things Yondu identified from his past:
"You can fool yourself and everyone else, but you can't fool me. I know who you are... I know you play like you're the meanest and the hardest but actually you're the most scared of all... I know you steal batteries you don't need and you push away anyone who's willing to put up with you 'cause just a little bit of love reminds you of how big and empty that hole inside you actually is... Just like my own damn parents who sold me, their own little baby, into slavery. I know who you are, boy. Because you're me!"
It was a particularly touching moment, but now that Rocket has seen all of his famiyl wiped out (he'll learn of everyone else's demise after watchng Groot die in his arms), it makes his moment of revelation even more profoundly affecting. He's literally just found what he needed and it's been torn from him once more.