In The Cooper/Kripke Inversion (S06E14), the university forces Sheldon and Barry Kripke to work together. Sheldon is none too pleased with having to work with Kripke as a team of equals, Kripke being someone that Sheldon not only sees as far more inferior in intellect and ability than himself (just as he does with most other people) but someone he also despises as a person.
Sheldon looks forward to reviewing (and presumably mocking) Kripke's research, expecting it to be unimaginative and of poor quality, so is quite upset when he finally gets a copy.
Later in the day, sitting at home with Amy:
Amy: Is everything okay?
Sheldon: I'm fine.
Amy: All right, well, how was work today? Did you exchange your research with Kripke?
Sheldon: Yes.
Amy: Sheldon, what's going on?
Sheldon: I read his research, and it's leaps and bounds ahead of mine. Which means the mommy of the smartest physicist at the university is not my mommy as I had thought. It's his mommy.
