You shouldn't put rinse water in someone's coffee.
Greg is making coffee for everyone for a client meeting at work, when he finds out that the sink isn't working.
Greg wants to find water to make coffee with.
Greg apologizes to the clients and offers to run and grab some coffee from a nearby shop.
Greg collects the water from the dish rack and uses it to make a pot of coffee.
The clients appreciate Greg's efforts, and their good mood affects their decision to continue working with the company.
The clients are disgusted by the coffee, which ruins their mood and causes the meeting to go poorly.