You Can't Do That by The Beatles is a song that delves into themes of jealousy and possessiveness within a romantic relationship. The lyrics express the frustrations and insecurities of someone who feels threatened by their partner's interactions with others. With its raw and confrontational tone, the song highlights the protagonist's desperation to maintain control and exclusivity in the relationship. The emotional intensity peaks when John Lennon delivers lines like 'I can't help my feelings, I'll go out of my mind' and 'If I catch you talking to that boy again, I'm gonna let you down and leave you flat.' These moments underscore the turbulent nature of the protagonist's emotions and the lengths they are willing to go to keep their partner from straying.