Let me tell you I am better acquainted with you for a long absence, as men are with themselves for a long affliction: absence does but hold off a friend, to make one see him the truer.
First and foremost, be faithful to your superiors, keep all promises, refuse the friendship of all who are not like you; and if you have made a mistake, do not be afraid of admitting the fact and amending your ways.
It is the steady and merciless increase of occupations, the augmented speed at which we are always trying to live, the crowding of each day with more work than it can profitably hold, which has cost us, among other things, the undisturbed enjoyment of friends. Friendship takes time, and we have no time to give it.
The service a man renders his friend is trivial and selfish, compared with the service he knows his friend stood in readiness to yield him, alike before he had begun to serve his friend, and now also. Compared with that good-will I bear my friend, the benefit it is in my power to render him seems small.
If friends disappoint you over and over, that's in large part your own fault. Once someone has shown a tendency to be self-centered, you need to recognize that and take care of yourself; people aren't going to change simply because you want them to.