I just filed my taxes for 2018, and had to pay in a significant amount of money. This got me exploring some of the details of my situation and  trying to figure out some of the math and the logic for certain things. I do have a CPA who helps me, but I'm a a Real Estate Broker and Investor with a background in Engineering, so I'm constantly trying to learn as much as possible and grasp everything I can with a solid understanding. 

My question is for those who have a DEEP understanding of the tax code.  I see all these seemingly arbitrary numbers and limitations and exceptions, and I wonder where they come from. I know that's way too deep of a topic to answer quickly, but If you really understand what they are trying to accomplish, do you think it's fair overall? Or do you think most of these rules are made to benefit a particular group that lobbied well? Things like deprecation deductions only being able to offset ordinary income up to a certain limit, unless you are actively engaged in real estate (something along those lines), Or biodiesel credits, but only if you do this, but not that.  Don't get hung up in the specific examples, because I'm ignorant when it comes to the tax code (that's why I pay my CPA) but I'm genuinely curious if people actually understands these things, or they just know the rules and follow. 

It's like there's a huge system of "if this, then that"  someone somewhere had to program into Excel and someone had to understand the logic completely to program it (write the tax code). I'm sure it has been many people over time, but you get the analogy. I wonder if some of you on here feel you have a good grasp on the logic, and if you do, do you think it's fair overall? Do you understand the caps and the exceptions? I know that's a loaded question, but i think it would be a worthwhile discussion.