Maybe it's a story where a glass of water symbolizes hope in a difficult situation. Like someone lost in the desert and that glass of water represents rescue and a new chance at life.
It might be a story where a glass of water represents a symbol of hope or friendship. For example, a person giving a glass of water to a stranger on a hot day and starting a beautiful friendship.
The story of Hangover 3 begins with the group trying to deal with Alan's problems. They end up getting caught in a web of trouble related to Chow. There are some really memorable scenes. For example, the scenes where they are trying to escape from the bad guys. The movie also ties up some loose ends from the previous movies in the series, and overall, it's a story filled with action, comedy, and some rather strange twists and turns.
I'm not sure which specific 'a glass of water short story' you're referring to. There could be many stories with that title. It might be about a simple act of someone offering or receiving a glass of water and the significance or emotions attached to it, like a moment of kindness in a difficult situation.