"Gah" is an interjection often used to express frustration, annoyance, or exasperation. It conveys a sense of emotional reaction, similar to saying "ugh" or "argh." People might use "gah" in response to a minor inconvenience or when something doesn't go as planned. This expression is commonly found in informal conversations, social media, and pop culture. It can be used in various contexts, such as reacting to a frustrating situation or when someone makes a silly mistake. Overall, "gah" serves as a quick way to communicate feelings without needing a full sentence.