Here's a sport you may have played with your business customers when estimating some functional changes for them.
1. Easy change that you want to do = 1 day development
2. Medium change that you don't really want to do but can understand why they want it = 2 days development
3. Change that you know could screw your design royally, cause problems down the track, make future changes a nightmare = 4 hundred million trillion days development
Do you try and spook your business customers away from dangerous changes by over-egging the development estimate? Make it impossible for them to even consider backing the change?
Do you sit with your customer and explain the danger in their change, try to compromise and find some middle ground that achieves the solution for them without compromising the system?
We are all guilty of bamboozling customers with tech-speak on occassion, maybe it's time we created a forum with our customers and found a way to communicate our concerns hopes and dreams for the software to them in a language they can understand.
Don't go terrifying your customers with scary estimates.