This is very interesting. Around when MongoDB was quickly becoming the cool thing to do I'd ask people about why it is better than just storing things in Postgres. People would have answers that would be grammatically correct but would not make any sense.

That being said, I find it weird that now it is cool to make fun of MongoDB. Some people on this thread have even said they want to know if a service is using MongoDB and they'd not use that service. I am pretty sure they'd be all over Stripe (who store your money related stuff in MongoDB) in a different thread.