What are some examples of "Early installment weirdness" in tv shows?

Before the introduction of Urkel, Family matters was a fairly grounded show centered on the Winslow family, it wasn't until later seasons when the show started to become zany.

The Breaking Bad pilot is also pretty different to the rest of the show, it features nudity and a lot of swearing, which is probably a relic from when the creators were aiming the pilot at HBO. And people like Saul and Mike were slightly different in their first appearances compared to their later incarnations. Mike was more chatty and Saul was more heavyset

The first season of the Office was also pretty different, the show was far more faithful to the original UK version, it had a balding and fat Michael Scott and a way more cynical tone, before the show became it's own thing in later seasons.