I'm an economics major but I find economics not to be exact enough, there is a lot of indeterminacy and experiments are not repeatable. Except this, it's very interesting. I especially like it when it's built upon axiomatic-mathematical systems where everything can be deduced from a few premises. This way the testing can occur on multiple steps and deductions can be double-checked with empirical evidence.
My favorite has always been physics but for various reasons I didn't pursue a degree in it. If I were able to land in a job that gave me enough time to do so, I would enjoy getting a second degree in physics. It's always been my passion.
Vortex: it's interesting that the reason why you like economics is exactly the reason why I dislike it, and vice versa

[basically, the fact that you can incorporate everything into an economics model [even though there are some pretty darn good econometric methods now]] Which branch of economics did you like most? Personally I go crazy for game theory, whereas I don't really like macroeconomics.