I'm sure there are some out there with a sense of entitlement - they think of the podcast like a radio show, produced every week, and if it doesn't come out then someone isn't doing their "job". I've seen it many times with podcasts...and online comics. In one case a comic artist got regularly beat up about not getting the comic out every M-W-F like he planned, but he had changed styles, improving all the time, and had trouble catching up. He almost gave up right then and there...
Some people don't realize that most of these things are done totally for free, for love of the subject, and what little income comes from web site advertising, CafePress shirts, etc. doesn't even pay the bandwidth fees for them.
I do think there is a profound sense of disappointment. The podcast can be a release for some. They can think about a future vacation at Disney rather than the day of work ahead (or behind, or during like me

), stuck in traffic, while exercising, etc. When they can't, all that other frustration multiplies. And sometimes it comes out in the wrong direction.