A selfie is a picture you take when you hate yourself.
It's also a picture best taken with a selfie stick, so everyone in the world knows your a total toolshed. It has the secondary benifit of providing a metal pole to more easily beat you with.
The best selfies are those that involve some kind of natural diaster or riot. It shows real class to demonstrate your ability to care about where you are like a tourist while people are being flayed alive by fire. With these kinds of pictures, it's best to wait until someone is actually in the process being brained by a police officer or torn to peices by rabid wolves before taking the picture, to maximize it's chance of going viral and earning you mad props, or as the cynical like to call them death threats.
In this picture selfie but someone pushed me into oncoming traffic and pissed in my mouth. Lol!