That's an opinion, not a fact. If I see a colored rectangle that's offset from the text with a label that indicates action[1], I immediately think its a button

That's an opinion, not a fact. If I see a colored rectangle that's offset from the text with a label that indicates action[1], I immediately think its a button. I'm willing to wager a non-trivial amount of consumers do so as well, but this is what things like context and split testing are for. [1] The trickiness with flat design is when buttons for action are also used as information display. One of the biggest issues with the first iteration of Metro was that you'd have a box that shows your current number of emails -- and you didn't know if that was just a part of your dashboard or also a link to your email that had a nice preview. That's not a failing of flat design, that's a failing of design.