Yes, not only one, but five good friends everyone needs. Even for the very best partner or spouse it would be to much represent all of them. These five friends should have very different characters and there qualities should be: cheerful, steadfast, truthful, discreet, and totally different than oneself.

The cheerful one will make you forget your worries with spontaneous activities and let you see your worries in a different light.
The steadfast is a good travel-companion, flexible and easy going.
The truthful one gives honest feedback without hurting.
The discreet one can be trusted with any kind of secret, even the most personal and is better than any therapist.
The last one of the five friends has nothing in common with you. He is different in age, social status, interested, ideas, goals, opinion. In short he is totally different than oneself and that is his advantage. He will give you new views input and challenges, expand your horizon.

And so older you get so more important it is to have at least one good friend from the young generation...