It felt like everything I thought I'd ever known was false and I could finally see the world for what it was and it was not a place I wanted to stay in.
You stop caring about what is right and wrong; the only thing that matters is your own feelings.
I would liken it to a sink slowly filling up with water. It feels innocent and manageable at first but when it starts to overfill, you rapidly lose control and chaos follows.
Everything around you can cause a negative emotion. That pencil on your desk? The guy that makes those is probably happily married with a stable income. I could also use it to kill myself if I wanted to.
Not only do you stop caring about right & wrong, but what once seemed right to you now seems like a waste of time.
"You can exist without your soul, you know, as long as your brain and heart are still working. But you'll have no sense of self anymore, no memory, no...anything. There's no chance at all of recovery. You'll just -- exist. As an empty shell. And your soul is gone forever...lost."—Remus Lupin on the Dementor's Kiss
"I'm afraid so. You're entirely bonkers. But I'll tell you a secret. All the best people are."