Common mistakes that make basement bathrooms feel creepy include poor or uneven lighting, leaving ceilings and pipework exposed, having unsafe dangling cords or outdated electrical outlets, and platforms with dangling feet. Lack of ventilation and noisy fixtures can also create discomfort. Neglecting warm paint colors or mirrors contributes to a dungeon vibe. Avoiding these errors by installing warm layered lighting, finishing the ceiling, securing footing, and upgrading safety devices transforms the space positively.