Physicist: That’s a really tricky question to answer without falling back on angular momentum. For example, the hands on a clock are spinning, and their angular momentum points into the face of the clock. So, in a cheating nutshell, tops stay upright because falling over violates angular momentum. The torque (from gravity) creates a greater and greater component of angular momentum pointing horizontally, and the friction slows the top and decreases the vertical component of its angular momentum. Once the angular momentum vector (which points along the axis of rotation) is horizontal enough the sides of the top will physically touch the ground.