Feedback is one of the most essential design elements. Snapchat has very little feedback telling you where you are in the app and it’s incredibly disorienting for users. Sure, you can say people will get used to it, but the point is they are having to switch from one mental model of how an interface works to another across apps, and phones. And not by choice, they are being force fed. The least Snapchat could do is include more feedback elements. A simple cookie-crumb type design (such as a small 3x3 grid icon) element could go along way towards orienting users, and could be an option to be turned off for more experienced or savvy users. I think Don Norman, Nielsen, and Jef Raskin would agree.