I have this habit of smiling and laughing a bit whenever I'm nervous. Recently my car broke down and I had to hitch a ride to the gas station. Some guy pulled over and picked me up. While driving he tried to make small talk, it was then that I noticed he had a knife on his belt and given that I heard all those hitching stories my mind raced with thoughts of me ending up dead on the road by this guy.
As I thought of this in the awkward silence between us I began to chuckle a little, I looked out of the corner of my eye and saw him glance at me with a stoic stare, this made me laugh a little harder. He asked me what was so funny but I just said its nothing. I then started to laugh harder thinking about how weird it would sound if I explained it to him.
He than pulled over the car and told me to get out, probably thinking that I was kill him or something hah.
So is it normal to laugh when nervous?