To know what it's really like, as opposed to what movies depict, just read the transcript of the famous Apollo 13 incident. Remember the movie version? Read what they really said here (http://apollo13.spacelog.org/page/02:07:55:19/). For instance:

Okay. And we're looking at our S—SERVICE MODULE RCS HELIUM 1. We have—B is barber poled and D is barber poled, HELIUM 2, D is barber pole, and SECONDARY PROPELLANTS, I have A and C barber pole. BMAG temperatures?

Less dramatic than in the movies. A lot more engineering and detail-oriented.