Even Sorcerers Supreme, old and new, can learn new things, and as Chavez (Xochitl Gomez) traverses multiverse America, he tells Strange and Wong (Benedict Wong) that the dream the former had was for the Strange variant that appears in the Opening scene died, actually was real of the film, they are a bit surprised by the news. In fact, Wong is quite concerned when he finds out that his dream of being chased by a clown in a tragically unclothed state actually happened to a poor variant of Wong out there. Towards the end of the film, the current Sorcerer Supreme has a brief discussion with Strange about happiness, confiding in him that he’s known for occasionally reflecting on his other lives. Chances are, the poor Wong variant who constantly misplaces her clothes while running from creepy clowns is one of the lives Earth-616 Wong will think about a lot after the film, whether he likes it or not.
Since the whole “your dreams are real” concept alone doesn’t seem to be annoying enough, the film also gives a very concrete example of a common bad dream and how it might play out in the MCU multiverse. When Doctor Strange encounters a Darkhold-corrupted variant of himself who has a rather questionable hobby of killing alternate universe Strange, the variant almost casually reveals that most dreams of falling the main Strange ever had are likely caused by Darkhold Strange killing other Strange variants in a way presumably involving great heights.
Of course, not all multiverse dreams are nightmares… but that doesn’t mean they’re any less heartbreaking. For example, Wanda can confirm the multiversal existence of her supposedly non-existent children because she keeps dreaming about them.