YES, BARB IS AN AMAZING CHARACTER. WE KNOW. But we have to give so much more credit to Mr Clarke.
The first reason is simple: He listens. No question is unacceptable. He's essentially what we wanted our teachers to be growing up – not condescending.
Without him the plot would have been so different and more people would have been killed. He's also integral to every breakthrough the kids have.
For example, he ran the AV club and gave the kids access to the Heathkit ham shack...
The ham shack was what was used to contact Will.
Mr Clarke explained in the simplest way to Dustin, Mike, and Lucas how alternative dimensions work.
Without his explanation the kids would have had far less knowledge about the Upside Down.
He also clearly explained how a gateway to another dimension would be easily detectable if one opened.
This helped Dustin to discover where the gate was.
IT TURNED OUT TO BE...
Mr Clarke is also responsible for what I think is one of the best moments in the entire season.
Without Mr Clarke's knowledge of sensory deprivation pools, they never would have been able to build one...
If he was like some other teachers, he would have not bothered to tell them. Mr Clarke wasn't like other teachers.
Remember he was also on a date that night. He still took the call.