Making things configurable is difficult, because it just explodes the testing space. Maybe that's okay for no-liability, here-be-dragons, use at your own risk

Making things configurable is difficult, because it just explodes the testing space. Maybe that's okay for no-liability, here-be-dragons, use at your own risk open-source software, but for proprietary software that you have to support, it's a clusterfuck to give too many options, because people will inevitably hit on the combinations of them that don't work and then you have to deal with it.