If a man says that he wants to go compass north, and you believe he is telling the truth, but he proceeds towards the compass south, he is mistaken. It is not a bad idea to try and cautiously advise him that he might be mistaken. This is a difference of information.
If a man says that he is frugal, and if you know that he could be much more frugal, maybe he has different standards of frugality than you. It is generally a bad idea to convince him that your idea of frugality is the right one. This is a difference of opinion, of values.
What is the difference between the above two situations?
(to be continued)