With all the stress from the ninja wars, somebody's gotta be having a good time, right? Probably Shikamaru - always bored and no motivation. I didn't notice this until a second watch but this society is pretty much founded on mind-altering experiences.
Everyone abuses ninja meth, which keeps you up for three days and makes you ready to die. Kiba gives it to his dog and nobody finds that weird. Naruto makes shadow clones of himself, each with unique consciousness but don't know if they're the original and only live for a few seconds - played for laughs instead of giving him existential crisis.