Answer:
You saw me where I never was and where I could not be. And yet within that very place, my face you often see.
The sharp slim blade, that cuts the wind. What is it?
The itsy bitsy teeny weeny yellow polka dot variety is quite popular.
Until I am measured I am not known, Yet how you miss me when I have flown.
What is the heart of many risks, has a heart, but is not a living being?
When is it bad luck to see a black cat?