Avengers: Infinity War is the culmination of 10 years of superhero movies. The film builds off 18 previous movies, with hidden references crammed throughout its runtime. The Marvel Cinematic Universe is known for putting Easter eggs in every movie, from comic book and pop culture allusions to callbacks within the series itself. Not only do these little bonuses make the films more fun, but they can also sometimes lead to wild speculation about the direction of the series. They aren't all just goofy jokes.
This extreme attention to detail makes it almost impossible to keep up with every little reference, and even the most astute viewers are bound to find things they missed in Avengers: Infinity War. Obviously, the film makes extensive allusions to the comic books that inspired the film, but not every Avengers: Infinity War Easter egg comes from the comics. While calling Drax Mr. Clean is a reference almost everybody would get, there are likely a few others that went over your head.