The American version of The Office started out, much like its British predecessor, as a comedic look at modern corporate life. In particular, it focused on the experience of working a dull job with weird people under an insufferable boss. However, as the series continued through its nine-season run, even the strangest and least likable characters became more human. From a storytelling standpoint, this makes a lot of sense. Keeping a character in the sweet spot of obnoxious but not despicable is a tall order. If a series runs for a long enough time, writers must choose a direction for their characters.
Source：https://www.cbr.com/the-office-reboot-new-boss/
