Disappointment is good. It keeps us (atleast some) looking for ways to change, upgrade those tools of thought, push against those limitations and breakthrough.
But it's not the only driver, so it's not necessary. Perhaps it's the strongest motivator, but I look for improvements in many things, often they're systems I don't use or products I'll never be able to afford. It's not disappointment that drives that (arguably it might be historic disappointment).
