Answer:
How can a pants pocket be empty and still have something in it?
What is the center of gravity?
Almost everyone needs it, asks for it, gives it. But almost nobody takes it.
Though I should be unique, you've made most of us the same. I would be stronger, if my characters were stranger.
You have it even if there is none.
I am your mother's brother's only brother in law. Who am I?
Easy
Animal
Difficult
Food
Funny
Kids
Logic
What am I?