Answer:
Where is the ocean deepest?
Almost everyone needs it, asks for it, gives it. But almost nobody takes it.
The buyer doesn’t want it, the producer doesn’t need it and the user doesn’t know their using it.
There's one in every deck of cards and in a famous movie
What has many keys but cannot open a single lock or door?
What never gets any wetter no matter how hard it rains?
Easy
Animal
Difficult
Food
Funny
Kids
Logic
What am I?