Unpopular opinion here from someone who has watched S1 3 times.
This season was boring and borderline cheeks. Felt like S2 was doing a bit much but this season felt like it should've been a 1.5hr to 2hr movie at best while completely omitting the evil Russians. Show also doesn't quite know what it wants to be now. They upped the gore significantly yet they regressed with the kid/teenager 'camp'.
The Billy & Max characters were useless last season and they still are - Barb's parents or Mike's Dad could've just have easily have been the 'Mind Flayer's primary host. The squabbling between Joyce and Hopper was forced and the segments with them, the conspiracy theorist and the Russian scientist were extremely boring - outdoing the Eleven/Kali episode in season 2.
The foreboding and suspense from S1 was minimized to an extent in S2 and it's completely gone in S3.
S1 >>>> S2 >>>>>>>>>>>>>>>>>>>>>>>>>>>> S3