In 'Birthday' by The Beatles, the song revolves around the simple yet joyous theme of celebrating a birthday. It captures the excitement and fun associated with someone's special day. The lyrics are straightforward, emphasizing the anticipation and happiness of a birthday celebration. Key themes include joy, celebration, and togetherness. The repeated chorus 'They say it's your birthday, we're gonna have a good time' underscores the infectious enthusiasm. There aren't particularly poignant moments given the song's upbeat and festive nature, but the overall feeling of camaraderie and celebration is a standout.