I see where you're coming from with Arrow. Personally, I think the first season was pretty good, the second season was amazing, the third mediocre and the fourth abysmal in every way. It's gotten so bad that I'm giving season 5 the three episode rule, so if its quality is anywhere near the garbage that was season 4, I'm not bothering, even though I'll still watch the other shows in that universe.

I couldn't watch The Walking Dead. I really enjoyed the first season, but I got so ridiculously bored halfway through the second season that it became too much of a chore to watch, so I dropped it. That's the only show so far that I've actually dropped, which says a lot.