24: There is a law of the television universe called the “Conservation of Family Goodness”. The total net goodness of any TV family must be 0. The more good one family member is, the more evil the other ones must be. If a family member disappears for some reason, their goodness or evil must be redistributed among the remaining family members.
The Class: There really is nothing funnier to American sitcom writers than English people. Or English people faking American accents. Or Americans faking English accents.
CSI: All the best ones die young.
CSI: Miami: No matter how stupid you think the show is right now, it just keeps getting stupider. David Caruso can heal people now, just by touching them.
Heroes: If you need a load of superheroes, in-breeding seems to be the way forward.
House: Sometimes, it's the simple explanations that are the most interesting.
Lost: When Lost dawdles, it's rubbish. When it starts explaining stuff, it's great
My Name is Earl: No matter how good you think the show is right now, it will just keep getting better.
Prison Break: All cabals and conspiracies require a cigar-smoking room for their headquarters.
Smallville: Lana Lang is the western world's biggest stalker magnet. She should be stuck at one end of Hollywood Boulevard to draw out the crazies.
Supernatural: After a while, the phrase “yellow-eyed demon” stops being scary and starts to become a bit funny.
Scrubs: Developing characters in a long-running show is a good idea.
Studio 60: Aaron Sorkin really can't write women well. Also, after a given point in any Sorkin show, it will actually become impossible to work out what characters are talking about.
The Unit: A show, no matter how good, automatically jumps the shark as soon as the psychics episode arrives.