I've done laundry for guys. My sister used to pay me and my brother to do her laundry. There were her clothes, my niece's, an my brother-in-law's. My sister's clothes weren't that bad. My niece's clothes just smelled like spit-up. My brother-in-law's clothes had special directions, and couldn't be washed with ANYTHING else.
You haven't seen gross until you've done laundry for a diesel mechanic. Not only were there underwear stains, but there were also grease, dirt, diesel, various mechanical fluids, cleaning solvents, and any number of other things.
I've also done laundry for a 10 year old boy and a grown man. The funny part was watching a 10 year old boy freak out because I was touching his underwear while I was folding laundry.