There are several kinds of love. One is a selfish, mean, grasping, egotistical thing which uses love for self-importance. This is the ugly and crippling kind. The other is an outpouring of everything good in you — of kindness and consideration and respect — not only the social respect of manners but the greater respect which is recognition of another person as unique and valuable. The first kind can make you sick and small and weak but the second can release in you strength, and courage and goodness and even wisdom you didn’t know you had.
From a letter that John Steinbeck wrote to his son, Thom, in 1958 after Thom confesses to falling in love with a girl at boarding school. Full letter can be seen here.