The characters in Quentin Tarantino's movies feel like part of the same universe, and whether the storyline takes place in the past or present certain key elements seem eerily similar in all of his films.
Tarantino also likes to include unifying elements that are obviously meant to be, like the Big Kahuna Burger or having a Vega brother in both Pulp Fiction and Reservoir Dogs, all leading to the unified Tarantino universe fan theory.
Quentin finally revealed the fan theory to be true during a recent interview on The Project, confirming that his movies all take place in the same cinematic universe, well, two universes to be precise.
There's the "realer than real" universe, which is where all the characters live, and then there's the "movie" universe within the "realer" universe that serves as entertainment for the characters.
Which is why Uma Thurman's "realer" character in Pulp Fiction describes the plot to Kill Bill to Vincent Vega when talking about her favorite TV show Fox Force Five...is your brain smoking yet?