The equivalent of tu existed in english in the old time (see Sheakspeare texts)
In France when you don't know somebody you say vous (you). This is the polite way to speak to someone else, or to a superior (boss, teacher ...) .
Now if you belong to a community like the Rotary, the LIon's club or your sport club, it's nice to say tu.
To a close friend you'd rather say tu, but in some social class (old school) they say vous. Even some people leaving in the same family say vous. (mère, vous me faites chier, Claude vous me ferez une petite pipe ce soir ...)
Yes even for a french people, the tu and vous thing is nightmarish. For example, one of my grand father was old school and a former high fonctionnary (sous prefet) : I never knew how to speak to him : tu, vous ? That's why I spoke to him, I say sentances starting by on (indifinite form of they)
at work I always say vous to nurse and my secretary, because it make their life simplier. I say vous, thus they say vous. If I say tu, they did not know how to react. As I am the boss, they won't know how to reply : vous, tu ( wich will imply in this case a form of intimacy or friendship). That's why I say vous to nurses and any others members of my hospital and tu at most doctors. But I will not say tu to every doctor, because some of them, would not appreciate this.
So the tu and vous thing, is sometimes nightmarish, but brings also many subtility in the communication