Basically, if you're an idiot, they're the people on the internet that try to aggravate you. This mostly happens to Justin Bieber fans, horny girls and guys on omegle, and idiots in general. Either that, or the troll just has too much time on their hands and trolls any random person for shits and giggles.
Stranger: m/20/california surfer with ton of tattoos, willing to share pics.
Troll: Cool story bro.
*your conversational partner has disconnected**