Why does Wong run away from the gods in the play, The Good Person of Szechuan?

When Wong first asks Shen Te to allow the Gods to sleep in her house she tells him she cannot because she is expecting a customer. However, when Wong leaves she changes her mind and welcomes the Gods into her house. Wong goes back to where he left the Gods, but after finding them gone he presumes they are angry with him. Frightened, Wong runs away.