Series you loved but don't now

The question is; What's a show you loved/liked upon first watching, but came back to rewatch and couldn't get back into, and why/why do you think that is? (This is why the spoiler tag, all the spoilers here if it helps explain)

Not talking about shows that fell off while you were watching, talking shows you liked the entire time you first watched them, but didn't once you tried watching again, because I think that's curious.

Example; I was really into Heroes during its first airing, but every time I've tried watching it again, I don't get past a few episodes.