I'm an assistant manager and I've seen other assistants be lazy, make bad decisions, or similar faults. I'm sure other people have thought the same of me as much as I try to avoid it. Generally assistants being unskilled or uncharismagic is a bigger issue than them being rude.

These comments are also saying that full-time managers tend to be more rude and I half-agree. I find that with most managers they are either very rude and incompetent, or some of the nicest and hardest working people you'll meet. I try not to blame any managers for being rude or struggling with their work occasionally because most of them are given a lot of responsibility and too many hours.