I enjoy using Unix terminals. I'm not sure why.
Can we ever be sure of why we've done something or feel a certain way? When someone asks me why I didn't like a movie, can I honestly tell them? If someone asks me why I chose to wear a certain shirt this day, can I honestly tell them?
Is the concept of the minimum amount of energy needed to do a simulation important in physics? It seems that if you could build a system which could simulate any physical event using less energy than is actually "needed" for the event to happen, then you could simulate arbitrarily "large" systems on your system. Presumably, the more energy available to do the simulation, the more complicated a simulation you can do. If your system can't handle running a simulation, simply simulate a simulation system that can (or a series of simulations of simulation systems, each upping the total computing power).