The fact that I can program in the highest level language and still have realistic, working tools to control machine code that is being generated or choose leve

The fact that I can program in the highest level language and still have realistic, working tools to control machine code that is being generated or choose level or type of optimizations or lets me change all of that case by case and during lifetime of the application kind of blows my mind (FYI, I am using SBCL).