Stress makes you dumb: Studies have shown stress and complaining decreases the size of your hippocampus responsible for learning and memory.
Repeated complaining rewires your brain to make future complaining more likely. Over time, you find it’s easier to be negative than to be positive, regardless of what’s happening around you. Complaining becomes your default behavior, which changes how people perceive you. And here’s the kicker: complaining damages other areas of your brain as well.