[Night Fury]

actually those tend to not affect me at all it's like how medicine that is supposed to make you sleepy only works the first time and after that I don't feel an ounce of sleepiness

I think it's more likely because other people's stress is getting to me and I sorta feel I'm not getting enough time to myself or something... so when everyone else is asleep, they won't need me to stop what I'm doing and listen, then I'm able to be more creative... ^^;
I maybe my worst enemy on this problem, fighting the sleepiness.

I didn't really understand it myself but I think talking to you I sorted out my reasons as to why, thank you