@ElleGray There's a small but growing shift for sales people to say as a meaningless departing nicety "stay hydrated" rather than "have a nice day". Yes, there is.
My body is amazing though. It has this superpower called "thirst" that lets me know when it wants "hydration", which we used to call a glass of tap water.
Enjoy your diet coke. I trust it will slake your thirst rather well.