<p>When I&#39;m watching someone else use a computer, and they&#39;re about to type a password, I avert my eyes, out of politeness. It&#39;s an ingrained reflex.</p><p>But the trouble with reflexes is that it&#39;s easy to learn slightly the wrong one, and have it go wrong in edge cases.</p><p>If the screen and keyboard are a long way apart – say, connecting a laptop to a big screen elsewhere in the room – and I was looking at the screen, then the instinct to look away is pointless, because I was _already_ not looking at the keyboard, which is the important part. But it&#39;s very hard to suppress.</p><p>Worse, the reflexive act of looking away from the screen can easily divert my gaze _towards_ the keyboard I ought not to be looking at!</p>