Humility. One of the first things forgotten by brands and their agencies. We love to make a product or brand more important than it really is; to make its promise far bigger than its reality. For a long time I've felt that what brands really need is a dose of humility, and the great contemporary brands like Innocent, Nike et al seem to more often than not get this.
Well, there now seems to be some fact to support this opinion. A study from the University of Georgia shows that too much hype can be detrimental. This builds off a lot of work in the field of affective misforecasting. Worth a read.