What causes wires to coil?

Wires coil primarily due to the way they are manufactured and stored. During production, wires are often wound around spools or reels, leading to a natural tendency to retain that coiled shape. Additionally, physical properties such as tensile stress, flexibility, and the material's memory can cause wires to remain coiled when not under tension. Over time, environmental factors like temperature changes can also influence their shape, causing them to coil further.