Becker's interest in criminology arose when he was rushed for time one day. He had to weigh the cost and benefits of legally parking in an inconvenient garage versus in an illegal but convenient spot. After roughly calculating the probability of getting caught and potential punishment, Becker rationally opted for the crime. Becker surmised that other criminals make such rational decisions. However, such a premise went against conventional thought that crime was a result of mental illness and social oppression.