Judaism has two terms for tranquility - "shalvah" and "menuchah." While they might appear to be similar, they really contradict each other.
Shalvah refers to a situation in which a person is not missing anything in life. He has everything he wants and therefore has no worries. He has a nice house with all the furnishings he can ask for. He has a large amount of cash handy to purchase whatever he wants. His business is going well, and all of his property and possessions are entirely safe. He has no enemies who would want to cause him harm. There is peace in his world. He is entirely healthy. He is respected and people accept his opinion. He has no competitors who are striving to diminish is stature. He has no obligations to others. He is successful at whatever he does. This is shalvah.
And it's a negative trait.
Why? Because if you feel that everything must be perfect, you are in danger that if the details of your life are not to your liking, you will suffer. The many difficulties that arise in your life will prevent you from experiencing pleasure and peace of mind.
Menuchah, on the other hand, is a virtue. It is a state in which a person lives with peace of mind since he does not need anything! Not because he has all he would wish for, but because his attitude is one of accepting his present situation. He will be aware that all benefits and damages in life are dependent on the will of the Almighty. He has trust that whatever is decreed for him is what will occur. If he has what he would like, that is good; and if he is not able to get it, that, too, is for the good. He does not feel anxiety about possible misfortunes. He knows that "every bullet has its special address," and he wants only that which the Almighty chooses for him. If you attain the trait of menuchah, you will feel inner peace regardless of your financial situation and whether or not you have the approval of others.
The person who has reached this level of not needing all that he would wish for is saved from all kinds of frustration. People will not have anything to criticize him for. Even if someone does wrongly accuse him of anything, he does not take it to heart. He knows that he is being accused in error, and is able to feel an inner joy. This level is called menuchah.
Seek to live a life of menuchah.
(see Rabbi Yosef Hurwitz of Nevardok - Madraigos Haadam; Rabbi Pliskin's "Consulting the Wise")