> I want to finish these shows, but every time I turn them on, I just feel kind of bored and empty, even though I like the show.

First and foremost you need to get your head around your own mind. No you don't like a show that you find boring and empty. That is the exact opposite of liking a show.

> Do you have any tips to avoid burnout on long shows?

Recognize that TV shows are for entertainment purposes only. Once you are not entertained MOVE ON!