This is a question asked in Quora. I found the answer to this question, a real one! Its written in the text that there exists a simple rule: a device should work absolutely perfectly without having to put a second’s worth of time into using it. The author has found Apple products, an example of such rule. Although she mentions “the moment someone else develops a phone that does all that and works with near, absolute, flawless perfection, I’ll abandon Apple and go with them”.