Guts
Gallbladder
If you stay up so long that you see the moon go down and the dawn come, people will say you have serious guts. It takes guts to stay up that late. More specifically, it takes a powerful gallbladder. Your gallbladder is sensitive to sleep changes, you know, so you risk a lot by staying up like that.
たん
きも
None
You stayed awake outside for so long, just to prove you had guts and powerful gallbladder, that you also got a sweet tan (たん) out of it!