This would actually make a very interesting meta post.

I've definitely been lead into strange and wonderful fandoms by readers that I love, candlebeck and pennyplainknits for the most part. Having a good reader in your ear is like a gateway drug into all kinds of things you swore you'd never get into:D

I think that something that makes unlistenable for me is similar to what you said: intense, negative emotions over a long period. It's too much for me, I take it in too much and it's so hard to disconnect from it. Whereas I could probably podfic the exact same thing myself without any problems. Which is weird.