What causes goose bumps on your legs when it's not cold?

Goosebumps occur when tiny muscles at the base of hair follicles contract, causing the hair to stand up. This reaction is triggered by various stimuli, including strong emotions like fear or excitement, as part of the body's fight-or-flight response. Additionally, factors such as a sudden change in mood, memory recall, or even certain sounds can also cause this physiological response, leading to goosebumps even when it's not cold.