Modifications to General Relativity or Why Theoretical Physics Baffles Me

I’m not going to lie. Theoretical physics baffles me. The entire idea that there are people out there whose job is to sit and think, “What if….?” and then design a model to try to find an answer is strange. But what really baffles me is the fact that these guys and gals manage to further science by doing this! Take Einstein, for example. Now, I have never bothered to read any biographies of the man, so I have no idea what his background was in experimental stuff. But the contributions that he is remembered for (general/special relativity, e=mc^2, etc.) are primarily theoretical stuff. He didn’t do physics in a lab. He did it in his head and on chalkboards and paper. But he still had one of the greatest impacts on physics in the 20th century (probably the biggest).