Don't flatter yourself that friendship authorises you to say disagreeable things to your intimates. The nearer you come into relation with a person, the more necessary do tact and courtesy become. [Oliver Wendell Holmes]
The offhand-looking art of deceiving stubborn diplomats could go a long way towards: "Speak the truth, as they never believe it." [Lesson from Camillo di Cavour]
It may be fit to give careful thought or ear to teachings that are said to be generally helpful, and even more fit to take the best and apply it well as time goes by.
For example, Taoist teachings contain a good meditation method, love-making tips, and one is meant to cultivate real wisdom. [Chang] [More].
There are many conform ways that are not good for man and woman and child and animals as well. Very murky waters are ahead. Can you prepare well in advance, you could end up with advantages that benefit such as your children and grandchildren.
Basic stand: "Good tools in proficient hands fairly often pay, but there is still more to consider in the wider picture."