having alters is like. Imagine a person inside your brain, or your favorite character or whatever. Anything. Put them in a situation. Say you want to imagine them on a beach, chilling out under an umbrella with a drink in their hand. Then you think "what if they got up and went to go for a swim in the ocean?" But when you try to imagine that, nothing happens. Like, they don't move. You're trying to picture it, but its not happening. Whatever you do to force the scene to change and the character to move, they don't You have no control over them. And instead they look over at you with this annoyed expression and they're like "I don't wanna get up and do that. I'm comfy right here. You can't make me do that." Or maybe something like "I don't like this actually. I'd prefer a hammock in the woods." Or "I don't want this drink, I'd rather have a sandwich." Because its not just a character in your head. Its a whole other person. A whole other conscious being able to make their own decisions and have their own thoughts and desires. You do not control anything they think or say or do, no matter how hard you may try.