Interest Stacks

Sequels that had a considerably worse reception than the first/previous seasons.

The most common causes is continuing a story that fans considered completed or a bad/rushed adaptation.

Not including reboots/remakes/alternative versions.
Not including airing seasons nor seasons from less than 2 seasons old after airing.
Not adding sequels that had a score higher than its direct prequel, no matter if its score is lower than the first season, for example:

S1: 8.5 S2: 7.4 S3: 7.6
In this case I won't add the third season.
Not adding inter-season OVAs either but adding sequel specials meant as finale.

This is NOT based on my personal opinion although I might leave it here but it won't have any influence on the scale.
This list is MAL's score-based.
With "best" season I refer to the season with the highest score.
Difference must be more than 0.50 points unless next season of a previous one that was put here has a lower score of more than 0.1