What causes your stutter?

What causes your stutter? I've always felt like there's a big misconception with stuttering, like people thinking it's caused my anxiety or nerves. Or because our brains are working faster than our mouths (or vice versa) something like that. I want to understand more of what causes it for everyone else. I know this is a question that not everyone here will truly know yet. But maybe this post can help you figure it out. For me, I stutter simply because I'm conscious of it. If I know it's there, I stutter. If I somehow forget about it for even a split second, I don't stutter. This means that I stutter even when I'm by myself, because Im still conscious of it. Basically the only time I don't stutter is when I'm singing or thinking