Why? Because there’s a sort of emotional whiplash that happens when your big dream comes true. You believed that the thing you wanted was going to satisfy you completely, or solve your problems, or make you truly happy. When it doesn’t, the resulting sense of loss can send you grasping for something else to fill the void. But then that thing doesn’t live up to your expectations, either, and the cycle continues. The positive psychology expert Tal Ben-Shahar named this feeling “arrival fallacy.”