I just completed a high level design of a new software process for a client.
But today I found out that the client's system already has a feature that can do what they want - it just has to be turned on and configured. They didn't know it was there. It would save them hours of implementation, not to mention that the feature is already tested.
So I told them that my design is ready, but also told them about this other software and recommended that they go with that solution. I have no issue with my design not being used.
I've worked with people whose egos would be hurt if their "baby" wasn't used, but I've never had any qualms about discarding my hard work if better ways present themselves.
I KNOW I'm good, so I don't need the validation. I know the client will be more impressed because they are getting great value from me.