I find that quote interesting. Your gamer friend might not have given you the context of the game, but it's interesting:

You pretty much know there is no cake. GLaDOS, the malevolent and controlling AI telling you there is cake, lies to you consistently. You catch on quickly that she's lying.

The warning "The cake is a lie" is scrawled in blood inside a hidden antechamber, inside one of the levels.

Somehow I feel like there are parallels here that you stumbled on more or less accidentally. Or maybe I'm being far too literary.