Are You Trying to Keep Your Body Guessing With Every Workout?

Is there a notion that you got to keep your body guessing in the context of fitness and workouts? Has that been debunked at this point? Or is that still something that like as a fitness expert? I mean, when I go to the gym, I don't say ha ha. It's Thursday, my body thinks that I'm going to train quads. Like it has no idea. But occasionally, the occasional suffering is probably a little bit of a good thing, right? Just like with working out, the occasional sufferings can lead to better adaptation.