One of my philosophies as a designer is that you should first start with the patterns that exist, and only break the rules little by little, in the right places. When [you] don’t break enough patterns, you end up with something boring and predictable. But when you break too many, you end up with something chaotic and confusing. There is a sweet spot, and it contains both the familiar and the new.
Jack Cheng (here, though post is only available to Kickstarter backers)