SOLVE THIS RIDDLE:

YOU COULD SEE ANYTHING IN THAT LIKE EVERYTHING AROUND YOU. YOU CANNOT EAT IT,CHEW IT,,OR READ IT.

HINT:IT IS A THING

Air

What is something that can't be filled in a cup? It tastes bitter and never sweet. The more you have it, the lesser you become.

Clue: It is not a need but most people keep