Honestly, I have no idea how two people can really have a discussion on humor or if something makes them laugh. I remember people raving about the Hangover films as comedy gold and I didn't laugh once at those. Meanwhile, the far less commercially successful Hot Fuzz had me in tears and laughing so hard I couldn't breath.
Guardians is somewhere in the middle for me, I smiled and chuckled a lot. It was quantity of jokes and I love the characters so I'm drawn in. I think that may be the key, if you go in indifferent it may not win you over, but if you love this world it is highly enjoyable.