He is upset because he sees Romeo at his party and their families do not like each other. Capulet tells him not to fight tonight, but Tybalt says that he wants to kill Romeo, but Capulet gets mad, and slaps Tybalt, because Capulet thinks that Romeo isn't trying to mess up the party, Romeo is just having fun, and talks gently without harming Juliet.
A thing that is or is likely to be wrongly perceived or interpreted by the sense THE ILLUSION MAKES PARALLEL LINES SEEM TO DIVERGE BY PLACING THEM ON A ZIGZAG STRIPED BACKGROUND
