Every once in a while I think of cool t-shirt texts for use, but rarely come up with anything. Some time ago I did invent one which I absolutely wanted to print for myself and after couple of months postponing the realisation finally managed to craft it. I think it turned out quite nicely!
According to the second law of thermodynamics, in a closed system the entropy will increase and can never go back. Entropy means that everything will equalise. If you open the door to your hot sauna the temperature in the sauna will cool when the temperature in the wash room will rise, but neither of them will be hot or cold afterwards. The universe is a closed system, and gradually the energy will come to an equilibrium. The energy levels will be all the same and the universe will suffer so called heat death where there is no more free energy available. Before that, everywhere where energy is used (and transferred to another form) there is a small fight going on against the looming increase of entropy. It can't go backwards, but it can be postponed, just for a short moment. That's what people are doing all the time.
Say no to heat death! Fight entropy today!