Like others here, I've only experienced positive at both DL & WDW. As someone who worked at DL while in college, I was was once coached on by a manager at DL that I wasn't smiling enough. I was hunched over cleaning up a baby bottle spill, I didn't realize I needed to have an "Im high" grin on my face for 8 hours. (Nope didn't say it to her but I did trip her on the CM bus on the way back to the parking lot

)
I don't think it has anything to do with training. Some people know exactly what to say to get through training etc, and when they get out on the floor, or on stage, they do the minimum to get by and screw around any chance they get. No matter how much training is provided, it simply will not stick with some people. IMHO, the best course of action for a guest, is to ask the cast member in question what their name is, write it down in front of them and ask directions to City Hall. At DL, EVERY guest complaint is looked at and filtered out to the proper managers. The managers then pull the CM in question into conference and they are coached.
It does seem to me, that once you have one bad experience with a CM, it seems to rain with them though. Rarely do I read trip reports with maybe one bad CM experience, it seems like there is either none at all, or a plethora of them. Weird.