Narcissists rarely accept the word ‘no’. They take up their victim’s time and spend their money. They borrow things and don’t return them, or return them dirty or damaged. They may violate physical and sexual boundaries and push verbal boundaries, enjoying making others feel uncomfortable with obtuse or rude comments or ‘banter’ disguised as jokes. They may have inappropriate social relationships with work colleagues and subordinates, crossing acceptable boundaries there.
Narcissists are drawn to those with naturally porous boundaries, who find it difficult to state and stick to what they find acceptable, who they can exploit easily in order to get what they want.