It's easy (or easier) to call your own app "stupid" when it's a single-person effort. As soon as you bring on other people to help, it's hard to call it "stupid" - not because the app changed and not because you think it's any less stupid at that point, but simply because by calling it "stupid," you're ascribing the label to someone else's work (which may or may not be welcome).

For a team to maintain that perspective (that their app is not going to solve world hunger any time soon) requires some real humility and open communication. You've got to take it seriously enough to produce quality work, but not so seriously that you convince yourself it's anything more than a stupid app at the end of the day.