Sometimes associated with the "Mass Effect effect", this feeling comes from the completion of the Mass Effect game series. Common causes include getting immersed so much in the game that after completion, you feel lost and/or empty, or realizing that the Mass Effect universe is so amazing compared to our own and you're pushed down by the fact that you'll never be a part of it.

To be less extreme, people may feel empty because they realize that no other game will ever be as immersive as the Mass Effect series, thus ending their gaming career forever.
A common outcome of Post Mass Effect Depression:

"No girl like Tali'Zorah nar Rayya exists in our world..."

*gunshot*
by robboelrobbo July 15, 2011
Get the Post Mass Effect Depression mug.
The worst possible ending in video game. It has never been yet surpassed since its reveal.
Person: Yea that ending was bad, but we all remember the mass effect 3 ending...

Other person: Yea, and that extended cut didn't help either!
by Awesomejawsom June 29, 2012
Get the Mass effect 3 ending mug.
The phrase used to bait gamers into a mindless debate either calling for BioWare blood in response to a sense of entitlement, or defending it from a lofty position of sophistication and arrogance - because everyone seems to know better than everyone else.
Friend 1: "So... you catch the Mass Effect 3 ending?"
Friend 2: "Yeah, I saw everyone on the internet going off about it. Fucking babies - it's a game, grow up. Learn to take disappointment blah blah blah..."
Friend 3: "Oh shut up. They totally fucked over the fanbase. It was really badly done - full of plotholes and bad writing and blah blah blah... BioWare/EA should patch it!"
Friend 1: "Oh for fuck's sake."
Get the Mass Effect 3 ending mug.