Plus, DID isn't just playing pretend with imaginary friends, either. You don't choose your alters. Your alters form themselves through severe abuse as a child, as Meowthkip mentioned. If you were sexually assaulted by your father as a kid, or beaten by your mom, you might have pretended to be another person to cope with the extreme stress. Because that's what kids do best: pretend. It's a lifelong condition that stems specifically from childhood, much like a bunch of other conditions do.
DID sufferers can't control when they switch personalities. Sometimes they just switch without reason, without anything to trigger a switch. I remember watching a documentary about a DID sufferer who once "woke up" and realized she had bought a really expensive car, yet she had no memory of doing so. They later learned that one of their alters had bought the car without them even knowing.
I get it. Separating yourself from reality is a coping method is comforting. I do it too. But pretending you have a severe, debilitating mental condition like DID isn't the way of going about it. I've seen so many Tumblr users do this and it annoys me.
