Some people crave or have to have some kind of flavor with their liquids or they don't want it. I have known multiple people who thought water tasted gross, which is somewhat legit because I had to get used to the different water taste when I went to school on the opposite side of town, but they just thought any kind of water was gross. They'd always have a soda or coffee or something.

My issue isn't flavor necessarily, its carbonation. But plain/unsweetened soda water is gross and soda streams aren't worth it to make my own infused water.