Thor: The rabbit is correct, and clearly the smartest among you.
Rocket: Rabbit?
T'Challa: Wakanda forever!
T'Challa: Today we don't fight for any life... we fight for ALL of them.
Natasha Romanoff: Where's your other friend?
Proxima Midnight: He will pay for his life with yours. Thanos will have that stone.
Steve Rogers: That's not gonna happen.
T'Challa: You are in Wakanda now. Thanos will have nothing but dust, and blood.
Proxima Midnight: We have blood to spare.
Rocket: Ooh, I would have washed that if I were you. The only way to sneak it off Contraxia was up my a...
Eitri: You're about to take the full power of a star. It will kill you.
Thor: Only if I die.
Dr. Strange: He could destroy life on a scale hitherto undreamt of.
Tony Stark: Did you seriously just say hitherto undreamt of?
Dr. Strange: Are you seriously leaning on the Cauldron of the Cosmos?
Tony Stark: Is that what it is? [Gets hit by the cloak of levitation] I'm going to allow that. If Thanos needs all six why don't we just stick this one down a garbage disposal?
Dr. Strange: No can do.
Stark: What is your job exactly besides making balloon animals?
Strange Protecting your reality, douchebag.
Wong: A hunk of Hulk of Burning Fudge is our favorite.
Banner: That's a thing?
Stark: Whatever.
Answer: Although many fans speculated it was because the Hulk fears Thanos after Thanos easily defeated him at the beginning of the film, the Russo brothers have since come out and said that it's because the Hulk feels that Banner only wants the Hulk around for helping him in fights, so his refusal to transform is a protest of sorts.
Phaneron ★
I think it's both.
Well it's not both. The Russo Brothers, who directed the film, have openly stated that the Hulk is not afraid of Thanos.
Phaneron ★