A powerful tool in the early stages of developing scenarios is to pretend the interface is magic. If your persona has goals and the product has magical powers to meet them, how simple could the interaction be? This kind of thinking is useful to help designers look outside the box.
Keep it simple: In general, interfaces should use simple geometric forms, minimal contours, and a restricted color palette comprised primarily of less-saturated or neutral colors balanced with a few high contrast accent colors that emphasize important information. Typography should not vary widely in an interface.
To our human minds, computers behave less like rocks and trees than they do like humans, so we unconsciously treat them like people.... In other words, humans have special instincts that tell them how to behave around other sentient beings, and as soon as any object exhibits sufficient cognitive function, those instincts kick in and we react as though we were interacting with another sentient human being.
It has been said that the great scientific disciplines are examples of giants standing on the shoulders of other giants. It has also been said that the software industry is an example of midgets standing on the toes of other midgets.