I wish I could un-know all that I have learned as a result of being a Territory Manager for Ecolab. My role was to go into various businesses and seek out opportunities to help them clean and sanitize various things. One aspect was dish machines (commercial dishwashers in restaurants, nursing homes, etc), where we would go in and test how much food soil was left on their plates and dishes AFTER they have been cleaned by our competitors. The degree of nastiness and the apathy on the part of the managers in charge of those establishments turned me off to eating at a rather large list of places that I used to frequent.
Another part of my employment was to become CPO certified (Certified Pool Operator). In this class, we got to learn all about how much parts per million of human funk that pool chlorine could attack and how much the average hotel hot tub had floating on the surface. Ever see a hot tub with foam around the edges? That's not soap.... just saying. Combine the heat, dead skin cells, sweat gland discharge, fecal matter from the dude that just couldn't reach all the Klingons circling Uranus, a little dribble of piss from the guy who had a little too much at Happy Hour and the man-fur from Chewbacca, the human sweater - you have a body-funk stew that even a gallon of Clorox won't touch. If your lucky the pool strainer will catch the solid parts. Don't even get me started on some of the acronyms involved. If you ever hear a pool manager refer to an AFR, get out now, scrub down and go home. An Accidental Fecal Release is just as it sounds. I'm sure there is probably and Intentional Fecal Release, but maybe they saved that code for a day I was absent.
I didn't used to be a germaphobe... but what has been seen cannot be unseen.