Cicero wrote around 2,000 years ago; yet his thoughts on friendship still remain convincing.
He says, amongst many other things:
That everyone could tell how many goats and sheep he had, but they were unable to count the number of their friends. Aside from being a nice piece of satire, this points to a question. How do you define a friend? Obviously that is harder than defining a goat.
What is sweeter than to have someone with whom you may dare discuss anything as if you were communing with yourself?
Retirement: you won't know what it's like until you get there.