There's an old saying, "Do as I say, not as I do."
That saying captures the fact people provide advice to others that is totally inconsistent with the actions they display to others.
Why do we instruct one way and act the opposite way?
We do we give advice to others that is inconsistent with our self-advice?
Do we treat others harshly and cut ourselves slack?
Yes and yes...frequently.
Do we provide better advice to others than we provide to ourselves?
Yes...frequently.
Why do we do these things?
In a word - Emotions.
Each of us has long-lasting and deep relationships with our emotions. Each of us has formed habits that are laced up in the emotion-legacies we experience as feelings. And, while our own emotions hold strong influence over us, we have far less ability to empathize with the emotions and feelings experienced by others. Consequently, the advice we give to ourselves is wrapped up in our emotional baggage while the advice we give to others is not (or, at least, the emotional baggage around it is much thinner).
Does that imply the advice we provide to others is better than the advice we give to ourselves?
Yes...at least the cold, hard logic of the advice is better.
On the other hand...No. The other person will quickly wrap up our logical advice in his or her own emotional baggage and so our advice will be distorted and, in the vast majority of situations, it will not be followed. Put another way, the other person will tend to cut himself or herself the same emotion-wrapped slack we would apply to ourselves.
All of this seems to point to the value of building something like 'reverse psychology' into the advice we provide to others. We can do this by refraining from giving advice to others and instead let others know the advice we would provide to ourselves if we were in the same situation. Then, we could be candid about the quality of our self-advice. We could let the other person know our self-advice has the habit of being laced with logic-defying emotional baggage. We could let the other person know our self-advice is quite often flawed to dysfunctional. All that said, the person may give thought to his or her own self-advice, inject some emotion-defying logic into it, and actually follow it. That would be a constructive outcome.
Later, seeing the positive results of the advice self-selected by the other person, we could choose to follow the advice we did not give.
Then that old saying could be altered to - "Do as you say and I'll do as you do."
Wouldn't that be a win-win!