It’s not that I’m not a friendly person but I really hate it when someone shortens my name before we are friends.
Nicknames are saved for friends, not people you just met at work or once through a friend. It’s so presumptuous!
I wouldn’t dream of saying hi B how you doing when there name is Barbara. Or hi Em instead of Emma, (is it seriously that hard to pronounce all the syllables there??)
Anyway my point is that it is just polite to wait until you are on friendly terms with a person before you decide its your right to shorten their name!