you might be conscience of your smile or maybe you don't think you will use the right words,or just insecure about yourself and worry about what other people think of you..i'm the same way around people i don't know
I do that too, I have pale skin and capiliaries close to the surface. Also, my skin is quite sensitive and will react easily to any change in temperature.
Used to happen to me all the time when I was younger. It was not fun. I wouldnt even know why sometimes. It got better with age.
