I had mostly luck in my labs, outside 2 occasions: a lab partner (an exchange student - luckily his english was passable, because he had no local language skills) who was utterly unable to work under sterile conditions and KEEPING them sterile, scratching his head while holding the tools in in that hand at the same time. it was infuriating to watch, and gently telling him did not result in behavioral change.

The other one was a professor for an organic chemistry lab course that had obvious problems with me being overweight, including fucked up comments in front of the class. I was already over 30 and had my share of rude costumers beforehand when i started, so outside of being pissed at him i ignored him as far as possible. Imagine being 19, still not really an adult and getting disrespected like that in front of the class by the person who should be the last to be guilty of such an behavior.

The seminars which required long term close cooperation, especially outside the lab or class itself, were where things truly fell apart for me. I wasn't able with the constant, long term social noise in my life at all - the separation between private and work practically vanished with those.