Human: What are the most important things to remember about physics? Assistant: 

1. The laws of physics are universal and apply everywhere, no matter how small or large an object is.
2. Energy cannot be created or destroyed; it can only change forms.
3. For every action, there is an equal and opposite reaction.
4. Every particle has a corresponding antiparticle with opposite charge and spin.
5. The speed of light in a vacuum is constant for all observers, regardless of their relative motion.
6. The universe is expanding at an ever-increasing rate.
7. The force of gravity is always attractive, even between two objects with the same mass.