For me personally, it's because water give the best hydration compared to something viral and trendy like Boba Tea. Most of these drink may help me cooldown, but make me thirstier than ever (thanks to the preservatives and sugars they're excessively use). Because of that, I have my own requirements for the new bottle I would buy to not less than 750-1000ml (which most of it, are standard drink bottle for my friends to have since they're small)