If I could hack my brain...
I'd play around with the mechanisms that control desensitization. I'd love to hear a favorite song with all the intensity and focus of the first five times I listened to it. I'd like to be able to stare at a magnificent looming tree for an hour and absorb all the aspects of its beauty in an almost religious trance. Or to not lose the intensity and sense of utter engagement the goes with the first weeks or months of being together with a new lover.
Of course there are some very obvious dangers that would go along with not being desensitized to the above stimuli, no matter how pleasant or profound they might be. Our brains deaden us to them for some damned good reasons. Losing oneself in the loveliness of a massive redwood out on the coast might be moving, but it's also an invitation to be eaten by a predator. And no matter how physically intense those first few months of chemistry are with a new love, being submerged in one another like that for too long would damage the larger weave of relationships that gives us our place in social and familial circles.
That and there is the small matter that our brains desensitize us to much of our environment because there is simply too much information. We don't have the processing power needed to pay attention to more than a small fraction of the inputs flooding into our gray matter at any given moment. Becoming deadened to varying degrees to the presence of objects and entities around us is a crucial act of neuro prioritization.
So, the ability to control those mechanisms would have to be extremely selective if wasn't going to be a burden or danger. That kind of fine control would likely require a network of tiny machine implants. Devices that could make the effects temporary and cut out after pre-set amounts of time.
Or maybe not. It would be interesting to experiment with lessening the level of desensitization so as not to take important things for granted in the long run. What's important? That leads us into topic of salience maps: the process that our brains use to embed emotions in the world around us, as well as imbuing the same feelings in the landscape of ideas and interrelated concepts within our heads.
Next up: Hacking the salience map.