What is the theme in Bus Stop by William Inge?

Friendship is another theme in the book. Bo and Virgil's friendship is a strong and long-lasting one. Older by twenty years, Virgil has taken care of Bo since the death of his parents and has become a father figure for the young man. During the course of the play, Virgil tries to restrain Bo, hoping to keep him out of trouble. He provides valuable advice on how Bo should act, especially with Cherie. With Virgil, Bo is able to finally express his loneliness.