Agreed on Seinfeld.
As for underrated - there used to be a show on Fox Sunday nights called The War At Home. Michael Rappaport was the lead but it was only around a few seasons. Awesome show.
If cartoons are also being mentioned I'll throw The Critic out there.
https://www.google.com/amp/s/nesn.com/2012/01/tom-bradys-pretty-boy-chuckle-cost-patriots-perfect-season-according-to-justin-tuck-osi-umenyiora/amp/
Wrong, Tom, you're only going to score 13.