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.
, after Sulu refers to the Tunguska blast of Siberia