I believe you have to be a willing participant in the listening experience. If you aren't in the right mind frame, or already predisposed to dismiss the info it won't be as effective. I think it requires you to quiet your mind and focus on the words, if you do that there's no such thing as being bored while immersed in the moment.
Jesse,
You're right about being in the right frame of mind to get the most out of the listening experience. It's like that for reading or practically anything else. If you are uninterested in the subject matter or disagree with subject matter of a book, you are most likely going to not finish the book.
If you take up a sport and aren't completely immersed in the sport, it won't be long before you find another to hold your interest.