Karma is not tit for tat. Karma is "like attracts like". It does not mean that just because you hit someone, they will hit you back. It means if you put out a constant negative energy, you will attract that negativity. If you spend your time picking fights, fights will find you. If you spend your time being loving, caring, and tender, you will find yourself surrounded by the same. Don't think of karma as an equal and opposite reaction, think of it as making your bed and then lying in it.