I've always looked at it from the perspective of who I'm designing for. From a functional standpoint, certain users respond to certain affordances in a design.

I've always looked at it from the perspective of who I'm designing for. From a functional standpoint, certain users respond to certain affordances in a design. For some, gradients and shadows are helpful when trying to discover points of interaction. For others, a flat colored element with a certain shape and hover color dictates the same thing. The fight between styles is unnecessary. Think about who is using what you make and their level of understanding. More importantly, though, never let aesthetics inform functionality. Rather, let functionality inform the aesthetics.