Nicknames, or Petnames... everybody has one, right? They're short, amusing or hilarious at times, and almost everytime called out with a hint of affection and suggests a sense of familiarity.
The origin of Nicknames are the most interesting part, especially if the birth of the nickname was in a friends' circle... one of my batchmates got bald and friends started calling him ganja (bald), one of my friend's surname rhymes closely with DVD, so people call him DVD, which later changed to dude as well!
People often ask me why I was/am called "scientist" by my batchmates. Perhaps because of my style of cracking PJs or some of my unique responses during a group BC (or chat), mixing scientific facts with nuances of our daily lives or perhaps because I got highest marks in the first exam taken in IIIT for UG2K5.
Whatever the reason be, Nicknames or petnames make life interesting and evidently show the level of innovation people can be capable of!
Nicknames or petnames are generally shorter than the name or has a more appealing intonation or meaning, or is amusing! For example, my batchmate and friend Manish Kumar Sharma is called MKS or Mux! My batchmate and friend Mohit was called Muggles (borrowed from Harry Potter Series by JK Rowling) which was later changed to Mugglu by others, and it really suits him, such a cute name! :D