(WYR) Which necessary biological function would you rather make unnecessary?
To be clear, you can still do the thing, you just don't need to anymore.
***EATING*** : You can eat as much or as little as you want and you will never suffer any symptoms of overeating or starvation, even if you never eat again. You also will not gain or lose weight unless you want to and your body will always function as if you are at your body's ideal weight.
(To avoid any 2-for-1 specials, your body now generates a consistently average amount of fecal waste regardless of how much you eat, but the solidity of your poop can still be affected by things like illness and medication)
***HYDRATION*** : You will never be thirsty again. Ever. In other words, you will always be perfectly hydrated even if you choose to eat salt and wash it down with seawater.
(To avoid any 2-for-1 specials, your body produces a consistently average amount of urine regardless of how much you drink, but the color and smell can still be affected by food/drinks/medication)
***SLEEP*** : You will always feel perfectly rested, even if you never sleep again. You can still choose to sleep, and can do so at will and for as long as you want (think of a duration and/or circumstance and you will automatically wake up when those conditions are met). You can also control your dreams, turn them off, or even make them extra random.
***DEFECATION*** : Your bowels become an infinite pocket dimension capable of storing all the poop you produce, forever. You can still choose to bomb the porcelain valley, if you feel so inclined (great for killing time at work or blowing up your enemy's toilet).
***URINATION*** : Your bladder becomes an infinite pocket dimension capable of harmlessly storing all the urine you produce, forever. You can still choose to empty the water tower at will (great for writing your memoirs in the snow).
***I LIKE LIVING ON HARD MODE (RESULTS)*** : I bet you like Souls games, don't you, you masochist.
Either that or you're just super lame. I don't know, I'm not your mom.