Answer:
You do not want me when you don’t have me but when you have me you don't want to lose me.
Flat as a leaf round as a ring. I have two eyes but can't see a thing.
I'm as simple as a circle worthless as a leader; but when I follow a group their strength increases tenfold. By myself I'm practically nothing.
Mary’s father has 5 daughters: Nana, Nene, Nini, Nono. What is the 5th daughter's name?
What has banks but no money a bed but no sleep waves but no ocean?
If it’s information you seek, come and see me. If it’s pairs of letters you need, I have consecutively three. What am I?