We asked six people to sort eleven samples from least to most reflective. No two orderings matched, and two were exact reverses of each other.
The vocabulary problem
Half the room was sorting by how much light bounced. The other half was sorting by how much the surface hid a fingerprint. Both called it gloss.
You cannot specify a finish in a language the workshop and the client do not share.
The fix was a physical card with the eleven samples on it, numbered. Nobody has argued about finish since.