If you have a habit of declaring milestones or changing them based on the crisis of the day, don't expect the team to remain motivated. Similarly, if the team isn't aware of the milestone and the value behind it, they are unlikely to deliver.
There's still always the possibility that I've gone totally, clinically cuckoo. But somehow I don't think so anymore. An article I once read said that crazy people don't worry about being crazy - that's the whole problem.