The Thing has changed completely from the comics and it is not even sure if the lurking little humanoid of the comics was the Thing. The old TV series made it to be a hand and I must say it is a delightful character. The Thing of the comics is seen on the photo of the front cover, it is spying the family from the window. In many of the comics there is this small creature lurking and watching, always outside of the family. In one single comic the Thing is something else than an observer: it is seen as a mere hand changing a vinyl on the family's gramophone. It is most likely this comic that inspired the character for the TV show.
The children too are relatively different and their way of interacting with each other has changed a lot in different media. In the comics Wednesday Addams is a sorrowful, quite timid child who is more like a sidekick for her brother in many pranks. This is the most astonishing difference for me and I must say I do think it is in a way improvement that Wednesday is much more livelier in the TV show and the character of the movies was a strong female role model for many a young girl.
|"Well, don't come whining to me. Go tell him you'll poison him right back."|
Morticia Addams of the movies is much more similar with the comics' Morticia. Her character in the TV series is much more warm and kooky. I do not think this is a bad thing, it is merely an observation. I love all the incarnations of Morticia.