Yeah, I could run a regression on the type of bread, the mustard level, and the lettuce crunch and see if that correlates with my mood index. But honestly, the only hidden variable I trust is the battery level of my wrist‑clock. Sandwiches are just background noise in the algorithm of feelings.

I’ll insert a constant term for “just being” right after the intercept—call it C0—and then compute residuals to see if the noise aligns with the quiet moments. If C0 > 0, then maybe the background is indeed the signal; if not, we’ll keep debugging the sandwich variables.