French, German and Spanish force you to pick a 'you' that reveals your relationship

French tu vs vous, German du vs Sie, Spanish tu vs usted: many languages make you choose between an intimate and a formal 'you' every time you address someone. Psychologists Roger Brown and Albert Gilman showed in 1960 that the choice encodes power and solidarity - equals reciprocate the same form, but between unequals the powerful give the intimate form and receive the formal one back. English had this too, until 'thou' died out and 'you' absorbed both roles.

— Roger Brown and Albert Gilman, The Pronouns of Power and Solidarity — In Style in Language, ed. Thomas A. Sebeok, MIT Press, 1960