Physics is great. It is great to know, how the world works, why the things do what they do and how everything is related to everything else.

Theoretical physics is something that changes this

into this .
Some might say that the second picture is less beautiful than the first one. However, if you understand what the extra stuff on the second picture means, new things emerge. You see that the protons of cosmic rays are the same protons as the ones in thermonuclear reactions in the Sun. These reactions create energy, which travels as electromagnetic radiation to the Earth. This electromagnetic radiation drives chemical reactions in the plants creating oxygen and so on. The equations in the second picture take away none of the beauty of the first. They add a lot of beautiful relationships among the objects and highlight the delicate structure of the environment, living or not.

And physics is my job. I get paid to know it, I get paid to teach it and I get paid to do it.