If that is your real name...

I recently started going by an abbreviated version of my name and some of my older friends have been struggling with the transition. My parents christened me Katy which has been a total nightmare most of my life. It is rare for me to be in a large social group or activity and be the only Katy. I think i spent a substantial part of secondary school responding to people looking for one of the many other Kates or Katies in my year. They also spelled it with a 'y' meaning that despite having a very ordinary name I still have to spell it for everyone. Kat is a much easier option and is also handy given that I'm a language student and 'Katy' is difficult to pronounce for a surprising number of nationalities.
Unfortunately my best mate can't handle the idea of me being Kat and every time I introduce myself as Kat he sighs or says its not really my name.
This transition really got me thinking about all my friends who don'g go by their birth names. My uncle goes by his middle name of 'Peter' rather than his birth name 'James' because this is the same as his father's name and caused confusion. I have 3 close friends who's real birth names I didn't know until we went on holiday together and they had to use their passport names to book! A boy in my Russian class goes by his middle name simply because when he was younger he decided he preferred it!
The most challenging was my parkour friends, at gatherings the majority of us go by nicknames and when we started hanging out in the non-pk world it was really difficult to call people 'Brendan' or 'Luke' or Kate' when you were used to hanging out with Twagger, Tenshi and Sprite.
I cant help but be curious if, at the end of the day, it really matters what you call people? Once you don't call them cruel names what does it matter what you call them? When you're friends you have nicknames, when you're a couple you have pet names so why does it matter what your birth name is? Sure 90% of us are named on a whim and it doesn't have any special meaning to it. I'm named after my aunties cat and my youngest brother was named Charlie so his name matched the rest of my siblings!
I don't wanna get too philosophical and prententious but does our name really mean anything? Its just a term to encompass all the traits assosciated with who we are to the people who know us. A label for the memories we feature in, an expression for the experiences we've shared. I like my name. Kat. One syllable, three letters; simple and easy to remember. That said, I wouldn't mind a cool name, something really random and unique like Domino or Spidergirl or something totally out there. A name with a story. With Kat the most common response is 'miaow'! Sure it could be worse. My mum nearly called me Millicent then things would really have been shit!