The phrase "what did I do to deserve you" can be interpreted in different ways depending on the context. It can be a sweet expression of appreciation for someones presence in ones life, or it can be a sarcastic remark implying that the person is undeserving of the others attention. The phrase has also been used in song titles, such as "What Did I Do (To Deserve You)" by Bryan White and "What Did I Do to Deserve You?" by Joey Ramone. In general, the phrase is used to express gratitude and amazement towards someones skills, presence, or actions.