Sheldon and Leonard in “The Cooper-Nowitzki Theorem”

Looking out at your fresh young faces, I remember when I, too, was deciding my academic future as a lowly graduate student. Of course, I was 14, and I had already achieved more than most of you could ever hope to despite my 9:00 bedtime. Now, there may be one or two of you in this room who has what it takes to succeed in theoretical physics, although it's more likely that you'll spend your scientific careers teaching fifth graders how to make papier-mâché volcanoes with baking soda lava.

Oh, good God.

In short, anyone who told you that you would someday be able to make some significant contribution to physics played a cruel trick on you, a cruel trick indeed. Any questions? [No one in the classroom says anything] Of course not. I weep for the future of science; now if you'll excuse me, the latest issue of Batman is out. Come, Leonard. [leaves]

[referring to his earlier failed experiment] Laser demonstration's looking pretty good now, huh?