That whole plot about people turning into "zombies" after spending too much time on the Good Place made no sense to me.

Tahani being basically the only human who wants to keep living forever seemed like a lazy ending to her character.

The Judge's decision to reset the universe to undo the thousands of years of brutal and unfair torture was clearly the right decision to make. So the selfish attitude of the protagonists of disagreeing with the Judge's decision and having convinced her not to reset the universe was also a very unsatisfaying solution that the writers created.

The Good Place is my favorite comedy ever, but those are the main reasons why some people hated the ending.