I hate to break it to you but it’s that sort of flowery promise that give people more cause to reject Christianity when the institution breaks it. Forget Prodigal Son, how about the shepherd who decided to go all the way because he let the lost sheep stray?
This is why I say to the OP, I wouldn’t advise being ‘brutally honest’ unless you’re ready to have someone’s history of disappointment slammed down your shoulders.
The office of a shepherd or a teacher is not given to every one of the sheep, you are correct.
*Not many of you should become teachers, my brothers, for you realize that we will be judged more strictly, for we all fall short in many respects. If anyone does not fall short in speech, he is a perfect man, able to bridle his whole body also. If we put bits into the mouths of horses to make them obey us, we also guide their whole bodies. It is the same with ships: even though they are so large and driven by fierce winds, they are steered by a very small rudder wherever the pilot’s inclination wishes. In the same way the tongue is a small member and yet has great pretensions. Consider how small a fire can set a huge forest ablaze.
The tongue is also a fire. It exists among our members as a world of malice, defiling the whole body and setting the entire course of our lives on fire, itself set on fire by Gehenna. For every kind of beast and bird, of reptile and sea creature, can be tamed and has been tamed by the human species, but no human being can tame the tongue. It is a restless evil, full of deadly poison. With it we bless the Lord and Father, and with it we curse human beings who are made in the likeness of God. From the same mouth come blessing and cursing. This need not be so, my brothers. Does a spring gush forth from the same opening both pure and brackish water? Can a fig tree, my brothers, produce olives, or a grapevine figs? Neither can salt water yield fresh. Who among you is wise and understanding? Let him show his works by a good life in the humility that comes from wisdom. But if you have bitter jealousy and selfish ambition in your hearts, do not boast and be false to the truth. Wisdom of this kind does not come down from above but is earthly, unspiritual, demonic. For where jealousy and selfish ambition exist, there is disorder and every foul practice. But the wisdom from above is first of all pure, then peaceable, gentle, compliant, full of mercy and good fruits, without inconstancy or insincerity. And the fruit of righteousness is sown in peace for those who cultivate peace*.
James 3:1-18
Still, Josh was only suggesting the Golden Rule, an attempt to imagine yourself in someone else’s shoes. It is not foolproof, but about as good as we are likely to do.