It's hard to say about a CM that is actually grumpy and taking it out on you - that's just unprofessional in ANY service field, not just Disney. I have empathy - I worked with the public for a long time - but you still can't act that way around customers. Disney employees a huge number of people, and I'm sure a few get thorugh who just aren't up for the strain of that kind of job.
However, I have met very nice castmembers, who are doing their best - but you can just tell something isn't right. We went to WDW and stayed at OKW right after the 3rd hurricane hit this year, and you could see the strain through thier happy faces. So we always asked how their families were, how they fared, etc. We wished them our bests and had a lot of patience when anything was amiss. You could see that just that small act of caring really helped their spirits.
Also - those poor brand new CM's who you know go home and panic every night over whether they're going to make it! We try very hard to smile and laugh no matter how long it took to check in that day! Everyone has to learn!