is this what they call a 'water cooler joke'?

There is a guy in office whom i give a drop to his home sometimes since his place is on my way to home. This day too, I met him in passage while leaving. He was leaving too, carrying his backpack and was filling his bottle at the water cooler.

As usual, I asked, "Need a drop?" and he answered "yes". Then I said, "But your bottle is full, why would you need a 'drop'?"
:)

The very next day, he was there again at the water cooler filling his bottle and there I was, armed with another joke which i had seen on TV just on the previous night.

I just asked, "Are you filling your bottle since there is a 'liquidity crunch' these days?"
:)