Probably should've clarified the color-coding system before posting...
the only 2 MCU films I straight up don't like were in red...Iron Man 2 and Thor 2: Dark World. Yellow tier films I don't dislike...but I do think that the ones ranked above are significantly superior. Guardians 1 did an excellent job with setting up the main cast and the humor is done really nicely. However, I think the character development is superior in the sequel, the villain is much more interesting and threatening in the sequel as well, and tbh I did not like Rocket at all in the first film. He's much more likable in the 2nd film because he's given more depth. In the first film, he comes off as an intelligent jerk without much more to his personality. Yes, this is developed much more nicely in the 2nd film, but I didn't like his character in the 1st film.
In general, while the cast was pretty decent in the 1st one, they were more memorable, likable, and better developed in the 2nd film imo.