Nicknames are often used to create or show a sense of comfort in the presence of another. When you give someone a nickname (or use the name they prefer), it creates a feeling of camaraderie and a greater sense of belonging.
It’s important, however, to ask the person what they prefer to be called rather than just assigning a nickname to them.
I always am amazed when people just assume that they can call me Bob or Rob when they meet me. When I lived in Boston, I was given the name Bert Sterling because I didn’t want to be called Rob and I had an overly excited reaction to the Yankees getting Sterling Hitchcock in a trade.
To this day, people closest to me call me Bert or Robbie or Bobby. But don’t even think about calling me Rob or Bob!