I work at a saltwater aquarium, and one of the guys that does our water quality testing legitimately has OCD. He is constantly washing his hands, even when he just touches something that isn't in the water. He's a good friend of mine, so I've seen first hand how bad his hands get. It's brutal.
It's the soap that does it, not the water. The soap is stripping your skin. In moderation it's good to wash your hands, but overdoing it can cause major problems. His skin is so thin and cracked now that it's got raw, open sores and hurts him. Unfortunately, it's hard to convince someone with OCD that too much hand washing can be a bad thing.
I personally just thoroughly rinse my hands between tanks (also what the entire aquarium staff at work does) and only consider using soap when I'm totally done, or if I've dealt with an infected tank. It's better for the fish this way too, because if you don't rinse all the soap off after hand washing, you're introducing it into their closed little tanks.
Huge fan and collector of Asian catfish (particularly Bagrids).My Display Tanks: 150g (+sump) planted tank, 60g (+sump) Sumatra blackwater tank, 30g Borneo blackwater tank, 55g hillstream tank, 30g H planted tank
In progress: 55g planted native tank