Capulet servants decidedecided to bite their thumbs at the Montagues, to playfully, spur on a fight. The quote states that the CapuletsCapulet's servants fight with the Montagues specifically because their masters are adversaries. TheirThe quarrel is between their masters, so the servants engage in altercations for fun. Evidence in the quote supports the Capulet's and Montague’s extreme amalgamateanimosity causes strife.