I recently heard someone say that a movie spin-off or continuation of a TV show never works. It works as a bit of nostalgia maybe, but it's usually a bad film. So, is it true?

Specifically I'm thinking movies that are set in the same universe or canon as the TV series that came before it. So something like Mission Impossible wouldn't count since the show and the films are different universes.

Also sometimes a film comes out during a TV series run, that's fine, it doesn't need to be after the series is over. I can also think of at least one example of a film kicking off a TV series, so that counts too.

(Also if there are absolutely terrible ones, let's talk about those too.)