Mary Elizabeth quickly considers Charlie to be her boyfriend. But even at the beginning of the relationship, there are problems. Mary Elizabeth seems to use Charlie more as a sounding board than as a sparring partner. She doesn’t pay any attention to what he wants. Instead, Mary Elizabeth likes Charlie because Charlie is such a good listener, and because he can act as a foil to reflect her brilliance. In some ways, the relationship is good for Charlie, since it provides him with comfort and stability. However, ultimately, the relationship pushes Charlie into the bad parts of being a wallflower. He’s not a person in the relationship, but rather, he’s Mary Elizabeth’s prop and puppet. Mary Elizabeth doesn’t physically abuse him, the way that Charlie’s sister’s boyfriend does, but she emotionally uses him. Mary Elizabeth isn’t a bad person, and she doesn’t treat Charlie horribly, but she also doesn’t let him be himself.
Charlie himself isn’t entirely blameless in the relationship, however. He becomes too comfortable in being a wallflower and doesn’t stand up for himself. But when he and his friends play Truth or Dare, Charlie’s inability to tell a white lie causes him to self-sabotage the relationship. However, in the long term, honesty is the best policy. Even though Charlie could have been kinder to Mary Elizabeth in the moment, he would not have been able to live with the lie. Charlie’s and Mary Elizabeth’s relationship would have persisted and perhaps even deepened if he had kissed Mary Elizabeth rather than Sam, but Charlie would have been denying himself his true feelings. Even though choosing Sam as the prettiest girl was the wrong choice from the standpoint of trying to mintain a functional relationship, Charlie’s honesty serves him very well in the long term. He is deeply sad and depressed when his friends won’t hang out with him anymore, but the blunt truth allows both himself and Mary Elizabeth to move forward with their lives. Lies and repression might help as band-aids in the moment, but in the long run, they will only cause more pain.