Your brain has a big job. Using connections throughout the body, it has to figure out what the body is doing and what it should want, and then it has to make that happen. Everything from reading fat levels in your blood to decide if you should feel hungry, to moving your legs to walk you to the deli, to parsing the visual stream to know you're looking at a sandwich, to remembering that language is how to get the sandwich, to putting together words to ask for the sandwich, to sensing how the sandwich tastes and whether you should come back to that deli or not. It is, in a very literal sense, you. A harder question to answer is what is the purpose of a feeling that you are you, not your brain.