That reminds me of one of the most embarrassing grad-school anecdotes I ever heard. A doctoral student in geology had been up all night for nearly a week cramming for his prelims and, in a meeting with his advisor, actually started having waking dreams. The advisor was showing him a slide of a topographic section that had been formed out of dissolved limestone and dolomite, and the poor guy half-dreamed he was looking at a collage of low brass instruments. He thought he knew the kind of instrument he thought he was seeing, but wanted to confirm it with his advisor. Herewith the brief conversation that almost wrecked his academic career:

"Tuba, or not tuba?"

"That is the karst, son."