An amusing pattern: I am most productive at work on days where I have shaved and tied my hair back into a ponytail.
I'm relatively sure that there is no causal relationship. True, I make the decision to groom myself properly before work some days, and to not do so on some other days, and perhaps that decision affects the rest of my day, but I see another more plausible connection: I only go to the trouble when I'm actually reasonably awake in the morning- that is, when I'm reasonably well-rested.