A quote from the low-budget sci-fi/fantasy film The Dungeonmaster, popularized by Adam Savage of Mythbusters, this quote basically means "you may be technically right, but you're not changing my mind." This can come off as stubborn, but it really doesn't matter, since you don't care about the technical "facts".
Person 1: Ugh this character's design is so terrible and pointless.
Person 2: Well actually, did you know that it's design comes from goes on to prove person 1 wrong
Person 1: I reject your reality and substitute my own.
Person 2: -sigh- Okay then, moving on...
by Kali_Gratitude_Rok7 August 21, 2018
Breaking the rules: like being able to kill the bad guy even though you already died.
Sword Art Online Abridged Parody: Episode 11

Kirito: I reject your reality and substitute my own.
Kayaba: "NICE!! Dungeonmaster!"
Kirito: "What? No! Mythbusters... What the hell is Dungeonmaster?"
Kayaba: "Oh. I was so happy there for a second."
by Animefangirl365 December 13, 2018
A phrase used by a person who likes to eat shit, to some extent knows that eating shit is bad for them, but doesn't acknowledge that fact and therefore dismiss it.

It can be seen as a modern analogy to Plato's cave.
Example (à la Patrick's wallet meme):

PC user: You know that the baseline Mac Pro costs 5 times as much money than a similarly-spec'd windows based machine, right?

Apple user: Yup.

PC user: And you know that you can custom build your own PC, right?

Apple user: Yup.

PC user: And even get a similar Mac Pro computer case?

Apple user: Yup.

PC user: And configure it to run Mac OS?

Apple user: Yup.

PC user: Then why did you buy the Mac Pro?!?!??

Apple user: Cus I reject your reality and substitute my own.

PC user: *facepalm*
by UwUltimateDoge June 20, 2020
i reject your reality and substitute my own
i reject your reality and substitute my own
by laughmaker5000 October 2, 2019
a one liner comeback that basically means that you're right and the other person is wrong. the 'realities' being the varying opinions in the argument/conversation

i reject your reality and substitute it with my own (i refuse to accept that you are right so i will change your point to mine)
teacher: i told you yesterday what the homework was. why isnt it done
student: you didnt tell me, therefore i do not know
teacher: why has everyone else done it then?
student: i reject your reality and substitute it with my own ;)
teacher: /mindfuck
by llamasareoverrated August 10, 2011
Quote from the movie "The dungeonmaster" 1984, and "Sword Art Online Abridged" (episode 11) ((Though the credits go to "Ghostbusters"))
Have you heard the quote "I reject your reality and substitute it with my own"?
-Yea, I heard it in "SAO Abridged"
Oh okay, it's from a movie called "The Dungeonmaster" from 1984
-Cool cool
by DanishViking April 21, 2017