Season 1: That first season was perfect it’s the whole reason the show became huge. No notes.
Season 4: Vecna, Eddy, Master of Puppets, just a great tight narritive of increasing tension. However the Hopper plot was stupid and over the top. Should have actually killed him or made him have to survive a year in the Upside Down, not end up in Siberia. The California stuff was also meh, but thankfully ended quickly.
Season 5: Incredibly bombastic, the first half and the finale were great, the rest of the second half not so much.
Season 2: The finale saved this season, it was was dark, Hob was great, but it was too depressing at times and lost a lot of the whimsy other seasons had.
Season 3: This season was a correction from season two that way overcorrected, this season had too much whimsy, the plot was just a little too ridiculous and the finale while fun was also a bit much.
Loved the show, I bet I’ll rewatch it again