The liking of certain things sometimes grows on you very slowly. I never enjoyed eating vegetables like sweet potatoes and squash when I was young, but as I got older I eventually developed a taste for them.
Rocks have likes and dislikes too. While it seems to us that they don’t seem to mind being covered with this coloured scaly stuff, lichens (and other things that grow over the surface of rocks ) do in fact grow on them very very slowly.
I wonder if people who work with stones and rocks for a long time might gradually develop a lichen for the same things.