I mean in the moment. If you are in the moment how can you not have all that you need? If I don't have it I must not need it. I might want it...but not need it.
Not buying it. At this very moment, you are burning calories, you will need more to continue living at some point. At this very moment, you are consuming resources that may or may not be infinite or renewable. Reality is not an infinite series of discrete infinitestimal moments as much as it is a continuous process.
I would find it very dangerous to live solely in the discrete moment. But I have to go to work soon.