What is the worst problem Romeo and Juliet encounter?

Romeo and Juliet face numerous challenges throughout the play, but one of the most significant problems they encounter is their families' ongoing feud. The feud between the Montagues and Capulets creates an atmosphere of hostility and distrust, which makes it difficult for Romeo and Juliet to be together. The feud also leads to a series of tragic events, including Tybalt's death, which ultimately results in Romeo's banishment from Verona and sets in motion the chain of events that lead to their tragic deaths.