His tone is deterministic in the way he labels Romeo as a 'lover', which sounds rather cynical, as though people are set and have no free will to do something else. Furthermore, Cupid is blind in Roman mythology, making the arrows of love he shoots seem random and ruled by chance, which is a pessimistic view of something traditionally romantic. 'Borrow' also diminishes Cupid's power, as though anyone might 'borrow Cupid's wings'. We can deduce from Mercutio's language, that he is pessimistic about love.