David Harbour has had it up to here with all these Stranger Things, thinks it's "time to end" the show
“It’s definitely time to end” Stranger Things, said David Harbour, the star of Stranger Things

All strange things must come to an end, and for what is perhaps the strangest of things, the Netflix television program Stranger Things, that time is next season. While many people rely on Stranger Things as a regular income, not all its beneficiaries dread the show’s conclusion. One of the show’s stars is actively counting the days until the Upside Down is closed for good: David Harbour.
Discussing TV with Discussing Film (via The Hollywood Reporter), Harbour remembers a time when he “never, ever wanted it to end.” That might be because it was a breakout role for the actor, leading to the plumb role of Santa Claus and the less plumb role of Hellboy. However, he’s ready to move on now that he’s in the Marvel Cinematic Universe and has replaced Tim Allen as Kris Kringle. That time has passed, and he’s ready to move on from hunting CGI monsters to becoming one.