Friendliness, like the other virtues, has two extremes and is only found midway between two vices. It is a lack of friendliness to show none at all, to seem rude and unpleasant, to look sad and gloomy, so that you freeze the hearts of those around you. (…) There is another vice at the other extreme of this virtue, which is to be excessively friendly; for instance, to embrace with a certain greediness, to say to each other 'Oh, how I love you. I wouldn't have missed seeing you for anything in the world.' This is excessive friendliness. [p. 94]

(St Vincent de Paul. From Jacques Delarue, The Holiness of Vincent de Paul, Geoffrey Chapman Ltd, London 1960, 132 pp)