Jensen Harris talks about deciding to make something that's familiar versus making something than expands on the original. (http://uxweek.com/2012/speakers/jensen-harris/) I don't think what he says is gospel, and I think he likes Toyotas more than any one person should, but he touches on the basic concept of changing what everyone is familiar with to something believed to make the original product (environment?) better or different enough to get more people using it. Check out the aforementioned link.