Birdy

Cowboy Bebop

Dragonball

Flame of Recca

Gundam Wing

Hunter x Hunter

Inuyasha

Mononoke Hime

Oddments

Outlaw Star

Ranma 1/2

Rurouni Kenshin

Trigun

Yuu Yuu Hakusho

Holy crap!
Many animes have a few stressful moments, but Killua has clearly gone beyond mere stress at this point.
 
Added: 3/21/09 From: Celga
 
Holy crap!