Cleaning this brass is a waste of time...

I did a weeks UML/Agile training/consultancy in Huddersfield recently. Relaxing in a pub one evening, I noticed two of the staff cleaning the brass drip-trays. Then I heard one of them say this

Cleaning this brass is a waste of time. It takes 10 minutes and when you've done it there's no difference.

I was immediately reminded of Jerry Weinberg's Fast Food Fallacy "no difference plus no difference plus no difference plus ... eventually equals a clear difference".