Answer:
If you lose me you may cause people around you to lose me too.
What is easy to spot but hard to find?
While you were folding a letter you got me. Usually you will do whatever it takes to avoid me but now you can't help but find me.
A spirited jig I dance bright, banishing all but darkest night. Air can't kill me but water can. Share me, I won't get less unless wind ruins me. What am I?
I will go within you and destroy you. Only because you wanted me too
It has no top or bottom, but it can hold flesh, bones, and blood all at the same time.