That I have to love thee doth much excuse the appertaining rage to such a greeting?

Romeo and Juliet, Act 3, scene 1. Romeo, to Tybalt.

Tybalt, the reason that I have to love thee

Doth much excuse the appertaining rage

To such a greeting: villain am I none;

Therefore farewell; I see thou know'st me not.

Tybalt just called Romeo a villain, and said that he hated him. What would be rage on Romeo's part is 'excused', or lessened, because Romeo loves Juliet. Romeo says goodbye; it's clear you don't know me.