Why Do Pets Get Odd Nicknames?

Is it just me or do all pet parents come up with weird nicknames for their 'kids'?
I know it's common for names to get shortened but I really do have a few strange ones, and equally as odd I respond to them all too!
My old feline house mate Max was fondly dubbed Fat Cat, mainly because he was huge (mainly fluff I must clarify) and quite laid back.
My current feline house mates also have shortened versions of their names, but mine are the most varied. So here goes, my list of nicknames in most used order;

• Pudding
• Kid
• Fluff (of course)
• Wingnut - I think this has something to do with my ears, but I belive there is a film production company of the same name so maybe it's after them?
• Spud and Sponge - normally this is after I've done something daft like walking into a table.

It's quite a variety but I'm sure other dogs must get this multiple name syndrome? Would love to hear some other nicknames, though I hope mum won't adopt any more, but at least I will know it's not just me that gets them!