Liberating Trust

The are few things more frustrating than being "let down" by someone who wasn't as good as their word. We've all experienced that feeling, whether in small ways like being stood up for a date or having the person who promised to help cancel at the last second, or in big ways like having our partner renege on their wedding vows or being unsupported by someone you thought you could count on. Frankly, if it happens often enough, or hurtfully enough, you may start to question whether you can trust people at all. But what about God? Have you ever been "let down" by God? How should we respond when it seems like God is failing to come through?