I feel I should pick this one because eight more hours of fun/productivity a day really adds up. However, sleep can be nice. Curling up in a warm bed is nice. Not being able to sleep again sounds somewhat of a waste, and we basically rely on feeling tired for that.
Probably the most miserable need is honestly bladder. No need to go into details, but everyone has suffered at some point. Never having to worry about that would be nice, especially if you can continue to eat and drink like normal. (Or even more junk because it doesn't matter.)
Social may be secondarily the worst. Imagine not caring about anything social. Some people come pretty close, but unlike sleep you can still engage in the positive aspects easily without caring a bit about the negative. It might put off others, but again, you don't care because it isn't a need.
