The finger.
When that Chinese teenager was losing his finger and don't remember about it, but said "I can't remember anything... but when I woke up... I was kind of happy.".
I found it kind of disturbing because it's not like when Stu lost a tooth in the first film, he must to live the rest of his life with one less finger. I would literally get crazy if I was him. How he was thinking that it's okay if he lost?