Lots of cynicism here, but most of it seems to come from what I refer to as "stock spieling". So to speak, basic spiels that feature no creativity or real point to them other than to prevent silence.
I don't like stock spieling. It's repetitive, and as mentioned prior, a bit annoying. This is especially true if you visit often and hear the same things over and over. Spieling shouldn't be sarcastic (unless it's being performed properly, as an obvious joke), repetitive, or annoying. Spiels should instead be engaging, memorable, and useful. Gauge those waiting in line before spouting off some boilerplate joke, and know what you're there to do. Only make jokes if you know they work, and keep safety at the highest of priorities.
Perhaps it's just bias speaking, but those I know who operate rides who have a genuine passion and enjoyment for what they're doing seem to understand this. However, a lot of these guidelines seem to be lost.