The customer was pretty low on water, so I decided to pour water on them.
What was your reason for pouring water on someone? Why not just give them a cup.
Why, don't you think this is a good idea? It's always about money with him. If I do nothing, he will steal the water from the tap.
You shouldn't treat customers like that. It's demeaning and it could end up someone getting hurt.
This is the customer abusing me.
The customer did not do anything to abuse you. You could get yourself fired for doing something like pour water on them.