Aside from the fact that you've got your negatives confused:
Grad students' assistantships often require them to teach classes. It's not "a way to build favor with the professor," it's required for them to stay in grad school.
As for whether they're "random" or not: how would you know how they assign classes? I doubt it's by lottery.
Grad students' assistantships often require them to teach classes. It's not "a way to build favor with the professor," it's required for them to stay in grad school.
As for whether they're "random" or not: how would you know how they assign classes? I doubt it's by lottery.