Depression is optimal for rumination/pondering. It signals that you and your current environment do not match the ideas you have about what you and your environ

Depression is optimal for rumination/pondering. It signals that you and your current environment do not match the ideas you have about what you and your environment should be like. Either change the environment or change yourself or change your ideal image of yourself or the environment. Your body doesn't exist for the sole purpose of self harm. It exists to keep you alive and have offspring. You could think of depression as a dynamically added constraint in a linear programming problem. When you add the constraints, the current solution becomes infeasible, indicating that you can't stay where you are, you must search for the new optimum. Using medication or telling people to stop being depressed is counterproductive, since it interrupts the process that the depression is supposed to kickstart.