It’s from a movie? I didn’t know. I thought I must have missed a good FR thread that had the explanation.
The Matrix. Red pill for reality, blue pill to stay in the illusion of the matrix.
Movie: The Matrix.
“The red pill would free him from the enslaving control of the machine-generated dream world and allow him to escape into the real world, but living the “truth of reality” is harsher and more difficult.
On the other hand, the blue pill would lead him back to stay in the comfortable simulated reality of the Matrix.”