Overheard in the Study Room

Two students doing a problem for classical mechanics, arguing over a pulley system. One argues his point by saying to the other, "it's an ideal world, right?"

I love this line because you hear something like that uttered so rarely, and it's even more rare to hear someone reply immediately by saying yes. (For non-physicists, an "ideal" system is one where cumbersome things like friction and air resistance do not exist.) For better or worse, physicists are a bunch of Don Quixotes.