Used to add emphasis and effect. For example: Why don't you leave me alone?
If those lines are the excerpt then the answer should be that Kelsey felt unsure of exactly what she wanted.
I think 1 is a full sentence, but I'm not too sure.
2 is a fragment, you can write something like "tom stepped from the boat after a rugged trip across the Atlantic"
3 is a full sentence, 4 is a fragment but I don't know really how to rewrite it.
5 is also a fragment and you could write something like "the cars hood, hot from the sun's ray burned to touch"
