You can always tell a real ...

You can always tell a real friend: when you've made a fool of yourself he doesn't feel you've done a permanent job.
 Laurence J. Peter

Quotes from the same author

An economist is an expert who will know tomorrow why the things he predicted yesterday didn't happen today.
 Laurence J. Peter
If you don't know where you are going, you will probably end up somewhere else.
 Laurence J. Peter
Life is a travelling to the edge of knowledge, then a leap taken.
 Laurence J. Peter
There are two kinds of failures: those who thought and never did, and those who did and never thought.
 Laurence J. Peter
Don't worry about middle age: you'll outgrow it.
 Laurence J. Peter