I was a graduate assistant in the psychology department. I was the assistant to two professors. With respect to capacity, I was a teaching assistant for both, and a research assistant for one. My primary task was specifically coordinating undergraduate research in the psychology department.
Co-workers were friendly. Time management wasn't bad as professors understood that there were class requirements. There was a lot of time to study as well.
I learned a plethora of things relevant to teaching, grading, research, analysis, management, to name a few.
I enjoyed the research aspect the most.