I was disappointed when
That '80s Show ended after just one season. I had watched it religeously every week, and was really getting into it. I enjoyed the flashback, and remembering the pop culture of the decade of my childhood. I agree it wasn't as good as
That '70s Show, but IMPO I don't think it was so bad that they had to end it like that. If they had done some more brainstorming and stuck it out a little longer, I bet it would have started getting better reviews, and it could have lasted at least a few more years. And yup, they left it a clifhanger. They were orriginally expecting to return for a second season, but the summer came and went, and no sign, or even word, of it returning. I remember I was so irritated.
I also wish
Roswell lasted an other year or two. It's ratings went down during the second season, which I agree was its weakest season, but they started rising again during the third. But (then) UPN didn't want to renew it, and basically gave it a death sentance. I suppose I can't complain too much, though. Three seasons is still better than two, and I think they ended it really well. It was near the perfect series finale I have seen.