What's a sound you find oddly comforting?

Checking a sidearm's chamber. Even if it's empty it makes me feel a bit better to know. I like the bright magazine followers that are white, light grey, or orange. I like orange the least but it's better than black. The orange shows up and shows there are no more rounds left. If I have a rifle, I'll check the rifle, but something about the convenience and knowing of having a round chambered and ready to go just let's me breathe a little easier.