I rewatch it a lot and the only season I skip is 9. There are a couple bad later episodes I'll skip but there are more than a few bangers in the later seasons.

Ditto here, season 9 ("Back to Earth") is the only one I have no desire to rewatch.

Season 12 is particularly good though. In my opinion, the first and last episodes of that season are among the funniest they've ever done!