Temperature, thermodynamically, is the quantity dQ/dS, which is sort of related to how much the internal energy of the system changes as the system gets bigger, or has more 'stuff' in it, it's like an average energy.<p>We experience temperature, however, as the amount of heat coming from an object. Really the experience of temperature should then be something like -dS/dQ which is like how readily the system gives up energy. The more entropy increases when the energy in the system decreases, the more 'hot' it feels.<p>Therefore, our 'experience' of temperature is like -1/T = -dS/dQ. The hottest temperatures are negative numbers close to zero.<p>Additionally, infinity temperature is simply the crossover point where adding additional heat begins to decrease entropy instead of increasing it. I.e. the places to store the additional heat are running out.