Okay, I don't like spreadin' the ol' hate around, but let's be frank.
There are 3 things I hate when it comes to books.
I'm sure there's many a writing site with rants on the first two, so I'll relax my *no hate* policy for the third one.
I. Hate. Nicknames.
In real life, sure, tons of people use nicknames. Thankfully, my name can't easily be shortened into anything weird or rhymed with anything obscene, so I made it through my childhood and adolescence without nickname-related-scars. But for most people, yeah. There's no problem there.
My cat responds/answers to... hmmm, I'd say close to 40 nicknames that he's acquired in the seven long years of his life with us. The dog, who turns three on June 1st, probably has around 20 nicknames. As the less intelligent of the two, (or perhaps I have it backwards...) she only responds to about half of those names.
So yes, I'm guilty of nicknames myself... but that's in real life.
On a page, in a book, I want simplicity. I don't want a character named 'Kimberley-Anne' where some people call her 'Kim', some call her 'Anne', or 'Kimmy', 'Annie', 'Kannie', 'Kan-Kan', and then others use her full name. I especially don't want an entire cast of characters, each with several names to keep track of.
If you're going to use nicknames, use them sparingly... please, only one character max per story.
And if you love to use a truckload of nicknames, please don't ask me to beta-read for you... I tell you, it's murder for a dyslexic person to keep track of so many names...