Just so you know, I'm not BU because it was absolutely shit.
Spoiler Alert*
It was formulaic
Eleven running away to meet Number 8 was just strange and completely unnecessary.
Number 8's band of 80s outlaws were completely ridiculous (compared with the fairly normal characters in Hawkins)
All the monsters was a really dumb, boring and over-dramatic plot device.
Introducing Bob just for Bob to die was lazy.
The ending of the whole series was just plain creepy. In series 1 (and a lot of series 2), the kids had a really idealised 80s childhood- great friendship, a secret club, charging around the town on cool bikes getting into adventures, communicating via walkie talkie, hanging out at the arcade. Then, suddenly, in the last episode they're having some kind of weir pseudo-adult, sexually charged slow dancing bullshit. Whaaaat?