Yesterday we had an anecdote about Zeuxis, so it seems appropriate that today one pops up about Phidias. From Benicia, inter alia:

There's a story I like about Phidias, a Greek sculptor working on the Acropolis. As he was finishing a statue of Athena, which would stand a hundred feet high next to a marble wall, an onlooker asked, "Why are you chiseling strands of hair on the back of her head where no one will see them or even know they're there? "I'll know," replied Phidias.

I don't think this one is ancient, though -- I'll happily be corrected otherwise ....