Differences in perception indicate differences in reality

The systems responsible for sensation are remarkably similar from one person to another, but each person uniquely experiences sensory input. Perception of the same event is likely to be different for different people. For example, water that is too hot for one person may be just right for another. The volume of sound at a concert may be painfully loud for one person but enjoyable for another. What are the factors that create these differences in perceptions from person to person? Do these differences in perception indicate differences in reality?