- Inexplicable perversity of human nature.
- The clever machinations of MongoDB's marketing people.
- The AGPL license killed it.
- We spent too long development before monetizing.
- Bad performance.
- Numeric types limited to a 64-bit `float`.
- Great product, but didn't/couldn't translate to revenue.
- Bad business model.
- Failure in timezones/timestamp nuances.