Hamlet's behaviour towards Ophelia in Shakespeare's play "Hamlet" can be attributed to several factors. Disillusionment with love, feigned madness, and fear of betrayal are some of the reasons for Hamlet's apparent meanness towards Ophelia. After his father's death and his mother's hasty remarriage, Hamlet becomes cynical about love and relationships, leading to resentment towards her. He may feel that love is fickle and unreliable, leading to his harsh treatment of Ophelia as a way to protect himself from further emotional pain.
Hamlet's erratic behaviour, including his treatment of Ophelia, may be part of his plan to feign madness and disguise his true intentions. He believes that Ophelia has betrayed him by obeying her father Polonius and spying on him, fueling his resentment towards her. His anger towards his mother for her hasty remarriage and his uncle for usurping his father's throne could be projected onto Ophelia, directing his anger and frustration towards her as a way to vent his feelings towards those responsible for his current predicament.
Fear of betrayal is another reason for Hamlet's meanness towards Ophelia. He may be mean to Ophelia out of fear that she will betray him, just as he believes his mother betrayed his father. His harsh treatment could be a defence mechanism to prevent himself from getting hurt. These interpretations are based on the context of the play, and individual performances or readings may emphasize different aspects of Hamlet's relationship with Ophelia.