While maybe not embarassing but in the epsode That Which Survives Kirk is a real jerk to Sulu and bites his head off 2 or 3 times when Sulu asks a question. The way Kirk treats Sulu in that episode does make me cringe.
here is one of the sayings.
"Mister Sulu, if I'd wanted a Russian history lesson, I'd have brought along Mister Chekov."
- Kirk, after Sulu refers to the Tunguska blast of Siberia
So is Spock in that same episode. He is so pedantic correcting everyone to two decimal places. Even to Scotty - a senior Officer.
If I were Scotty in that episode I would have punched Spock - he deserved it.
I don't regard this as a good episode because of this