Do you ever start a show knowing it was cancelled?
I recently watched HBO's The Time Travelers Wife full well knowing there was only one season. I think I mostly regret it. I loved the show, and knowing there won't be any more to watch has bummed me out for the past week. I can't remember feeling this way about any other show - it sucks.
If you liked The Time Traveler's Wife then keep an eye out for Journeyman. It also only had one season, was also very Time-travely. Still worth watching.