Two things that have been annoying me about podcasts:
The first is specific to the Science@NASA podcast. I'd give you a link to NASA's page about their podcast rather than that nasty link to the XML, but there isn't one. There is though a page describing various ways you can be notified of new content, including the podcast, and an RSS feed.
The content of the podcast is excellent, and timely, and it's good to see such a large and important beuracracy giving something back... but it's bloody annoying when Dr Tony Phillips (who otherwise does an excellent job) says things like "Pictured to the right" - well, no, actually, a podcast is audio-only, there's no picture at all. Likewise, he'll read directly from the page "Click here to find out more". I find the phrase "Click here" offensive enough in text - I firmly believe that if you have to tell people where to click you're not communicating very well. To put it in audio where I can't possibly click - and where I can't even see where his putative 'hyperlink' is taking me! - is just ridiculous.
I've just unsubbed from that podcast for that reason; I can't take any more of it, and although it's a good podcast, I get much of the same news from Slacker Astronomy.
The second annoyance is that so many podcasts do silly things with their tags. Many of the things I think are silly might make more sense on other players, so I'll leave them aside for the moment. There's one thing that is inexcuseable though - having the "Title" field commence with the date. For one thing - it's podcasting. I listen when I feel like listening - the date you recorded or released it is irrelevant. Even worse though - when I'm scrolling through my "Unplayed Podcast" playlist, I can't tell which podcast a particular item is from, when all I can see is the date..