In Infinity War, Star-Lord failed the entire Marvel universe and proved to be the worst hero. While nearly all Avengers along with the Guardians assemble to fight The Mad Titan, Peter Quill was one of the reasons why Avengers lost against Thanos. Many heroes did put their differences aside for the greater good in Infinity War, whether it was the battle on Titan or the climactic battle of Wakanda.
The film’s tone was apocalyptic and grim, so a little comic relief was a break from the tension that was built up. Guardians came into the picture after they answered the distress call of Asgardians and found Thor as the only survivor after Thanos’ attack. After joining Thor, the Guardians did provide a bit of comic relief with some hilarious scenes. For instance, the one where Drax called Thor “a handsome pirate angel”.
Peter Quill, however, wasn’t too pleased with Thor as he thought that his presence might steal away Gamora from him. His behaviour only worsened as the movie moved ahead which proves that he has not matured at all since Guardians Vol 2. Gamora makes him promise that he would rather kill her than letting Thanos capturing her.
He was now placed in a tough situation and it’s understandable that he didn’t want to shoot the woman he loved. He eventually did so as Gamora pleaded but the entire ordeal ends up amusing Thanos. The Mad Titan then tells Quill “I like you” which wasn’t a praise or validation but rather a condemnation.
When the Guardians meet Doctor Strange, Iron Man and Spider-Man, Quill again hides behind his swaggering machismo even calling Tony Stark’s plan bad while claiming he could even dream a better plan than that. Star-Lord even pointed out that he is half human and his human part is something that’s “stupid”. Unfortunately for the heroes, Quill’s stupid human side took over which cost Avengers everything.
Upon hearing the news of Gamora’s demise, Star-Lord loses his cool and ruins the plan. Thanos then got free and overpowered all other heroes with Doctor Strange surrendering the Time Stone ultimately. So, one can say that if Thanos won, a major part of it goes to Peter Quill as he was the worst hero.
But as revealed by Doctor Strange, Star Lord’s actions could be the part of the secret plan of Strange. The Avengers only win in one future outcome and if Star Lord’s absurd behaviour is a part of it, it could act as a saving grace to Star-Lord’s behaviour.