Because that's pretty much what I've been looking for my almost entire life
I come from mainly from MMORPGs but I also played a fair amount of "virtual worlds", like IMVU, Second World, OurWorld and many games I can't remember anymore. I just love making my own character and making a story around it that I can live through, and get other people engaged in...
plus I'm really freaking lonely so gaming is my way of making friends don't judge