I don't know if I've ever gone from hating a show to loving it again, but there have definitely been times when I started losing interest or becoming frustrated, only to get into it again.

I stopped watching Supernatural twice, first during season five and then during season six, only to start watching it again pretty randomly and getting sucked back in.

I lost interest in Fringe a couple times. Not to the point where I stopped watching, but to the point where I'd multitask or channel surf when it was on, and didn't mind if I missed some things. But then I got back into it more, and I grew to really love the plots in the other universe (even though I was initially uninterested in those versions of the characters).