Who's Who?

Ever notice working in a large company people have names that they go by, but when you try to look them up to email them or call them they are not in the system under that name but under there real name.  Like someone may be called Barbara but in the system her 1st name is Johanna with a Middle name showing up as B.  How am I suppose to know that?!?!  If you are going to go by that name why not make Barbara the name that is displaced and then when you look at the person's profile there full name would be displayed.  You almost need a cheat sheet to know that: Jim goes by Rusty and David goes by Lenny.  Who's on 1st and what's on 2nd.