Good Riddles

Question: You struggle to regain me.
When I'm lost, you struggle to obtain me.
I pass no matter your will,
but I'm your slave to kill.
What am I?

Question: A man is stuck on an island with his best friend and a fisherman. The fisherman and his best friend go off to catch food while he builds a hut. The fisherman returns alone with some salmon he had prepared. His best friend had fallen off a cliff.

After he is rescued from the man goes to a diner and he orders salmon. He eats his meal, he pulls out a gun and commits suicide. Why does he do this?

Question: A man and his son are in a terrible accident and are rushed to the hospital in critical care. The doctor looks at the boy and exclaims "I can't operate on this boy, he's my son!" How could this be?

Question: A man leaves his cabin and travels 100 meter north, 100 meters west, and 100 meters south just to arrive back at his home. He sees a bird. What kind of bird is it?

Question: The more you take, the more you leave behind.
What are they?