As stated in the Sci Fi Series, Fringe (#3 in the list of Fringe), deja vu occurs when you have done something before, hence feeling you've done the same as what you're doing in your reality. In truth, you've done it, but in an alternate reality.
Tom: Woah, Dude. I totally feel like I've seen that chick before.
David: Yeah, man, I know.
Tom: Well she wouldn't ask me out even if it was in an alternate Reality.
David: Yeah, man. Totally.
Tom: Just a rush of Deja Vu.
David: Yeah, man, I know.
Tom: Well she wouldn't ask me out even if it was in an alternate Reality.
David: Yeah, man. Totally.
Tom: Just a rush of Deja Vu.
by SouperSecret July 12, 2009
Get the Deja Vumug. I’ve just been in this place before!
Higher on the street
And you know it’s my time to go!
Calling you!
And the search is a mystery!
Standing on my feet
It’s so hard when I try to be me!
Woah!
Deja Vu!
Higher on the street
And you know it’s my time to go!
Calling you!
And the search is a mystery!
Standing on my feet
It’s so hard when I try to be me!
Woah!
Deja Vu!
by Sanic Yeet January 26, 2020
Get the Deja Vumug. by Wharon November 23, 2021
Get the NOT deja vumug. Maybe that's why we get deja Vu...you have a dream in your subconscious while you're sleeping, but since your brain experienced that for such a long time, your conscious self starts to pick similarities and scenarios out from your environment. And because most of the time it's identical, you feel that you've been through that before. But you don't remember it because you have a dream in your subconscious mind, not your conscious mind, and although they're technically connected to each other, your subconscious experiences have very little affect on your conscious memory. Maybe that's why you sometimes wake up and find out you woke up in the middle of the night and did something weird, but you don't remember it, because at the time, you're consciousness is stuck in some kind of limbo.
Frank: "hey Ricky?"
Ricky: "ya, Frank?"
Frank: "I feel like this happened already"
Ricky: "Deja Vu?"
Frank: "Deja Vu"
Ricky: "ya, Frank?"
Frank: "I feel like this happened already"
Ricky: "Deja Vu?"
Frank: "Deja Vu"
by Man_like_body_god_like_thought May 28, 2018
Get the Deja Vumug. I've just been in this place before
by DaveRodgers69 January 26, 2020
Get the Deja Vumug. 
When a conversation occurs more than once.
Bobby: "So my Aunt has a couch made out of llama."
Billy Bob: "I'm getting conversation deja vu. Didn't you already tell me this?"
Billy Bob: "I'm getting conversation deja vu. Didn't you already tell me this?"
by CriptheCripple January 12, 2017
Get the Conversation Deja Vumug.