And his "new element discovery."

Sheldon should have someone proofread his papers.

He should, but he wouldn't, because of course Sheldon doesn't think he makes mistakes.

And how could anyone else, who obviously would not be nearly as smart as Sheldon, possibly proofread anything Sheldon writes?

The Bat Jar Conjecture, (S1E13)

In Physics Bowl Sheldon rejected the correct, final answer provided by his teammate--the Soviet Physicist/Janitor (Go Polar Bears!)--and lost the competition for his team.

One of the biggest mistakes one can make is to think they're always right. It also won't make them any friends.

https://www.youtube.com/watch?v=yACh9njgjtY

https://www.youtube.com/watch?v=_mPmxEnLx1Y