I was thinking about water for a while. I recall watching a true life reconstruction of a disaster where two fishermen lost their boat and they were stranded in the ocean on a life raft. It wasn't long before they ran out of fresh water. They were surrounded by the ocean but they couldn't drink it because it would make them more dehydrated. The water was salty. One of the men gave up and drank the sea water, his organs shut down that night and he died.
If you can purify water, you have an essential skill. Perhaps one day, the water won't be safe to drink. Perhaps a disaster would cause the water to be poisonous.
When you're very thirsty, plain water tastes the best. Sometimes the only drink you need is water.
