"Rule 11: Which database technology to choose:
Choose SQL when you need to do ad hoc queries and/or you need support for ACID and transactions. Otherwise choose no-SQL"
I think it should be the contrary: SQL by default, no-SQL if you have a specific need and know what you are doing.
Netflix's analogy is great, and I would add: being charged $0.01 per minute of viewership is so stressful you would consume less, or you would be stressed about what your parents would say about the bill.