I have always been Catherine. I had to correct a teacher once, in year 7, who was calling me Cathy. I was ignoring him, at first because I did not register it was me, and then to make a point. He eventually added my surname to Cathy. I replied "my name is Catherine." He apologised.

My SIL asked permission to call my daughter Ellie - but she never has, it does not suit her.

We considered Madeleine for her, but the thought of her being called maddy made me cringe (and it was a very popular name)

I know people who have used the short version (Sam, Wil, Ben) and had to correct people who try to lengthen it.