A large part of the problem is that most of the touch device UI is “discoverable.” There is no indication-or reason to believe—that a long press might do someth

A large part of the problem is that most of the touch device UI is “discoverable.” There is no indication-or reason to believe—that a long press might do something different than a tap, or that a swipe might reveal an option (or that a swipe in the other direction will reveal a different option), etc etc. it is all extremely opaque, not entirely consistent between applications, and completely different between OSes.