My name is Bonnie and growing up kids were always asking me what it was short for... like Bonnie was a nickname for some other name. I had to tell them it was my complete name. My middle name is Ellen, which I always felt was a more grown up name, but I never took the jump to trying to get people to call me Ellen.
My husband's sister was Katherine, but always called Kathy by the family. Somewhere along the line, while she was off living in another state, she started going by Katherine. We are the same age, but she didn't marry until after 50. At that point, she asked me pointedly to call her Katherine. I just couldn't do it! Not after a lifetime of knowing her as Kathy... it just felt too stilted and formal, like someone else's name. So I just didn't refer to her by name anymore. I've always hated it when people change their name, midstream, and expect you to fall in line. I just can't do it.