Everyone is different, you're right it depends on the person. If we all go back go our original worlds then what happens to you?

[ Wouldn't it be bad for the older Nier to return home? He simply just wouldn't exist. There's no if ands or buts. When you stop existing then there will be nothing left. That seems a bit sad somehow. He's heard of how things turn out. ]

I think it's better that you're alive and you're here now.