What Am I Riddles

Question: When you fall in me your as happy as could be, but you fall into depression when you lose me.

What am I?

Question: The person who buys me doesn't need me, the person who makes me doesn't want me, and the person who uses me can't appreciate me.

What am I?

Question: I am greater than God, more evil than the devil, the poor have me, the rich don't, and if you eat me, you'll die.What am I?

Question: He has married many women, but has never been married. Who is he?

Question: What belongs to you but others use it more than you do?