Answer:
I come with a train and go with a train and the train doesn't need me but can't go without me.
Sometimes I am white, sometimes I am dark. Most people love me. What am I?
I flow from the Homerβs mouth when he sees doughnuts.
The more of this there is the less you see. What is it?
I am good at concealing what's real and hide what's true. Sometimes I bring out the courage in you!
What do you purposefully put lots of in and on your body, but run away from when you encounter it outside?