Quote from Dr. Love
It's mostly his facial expressions.
Like this one.
The manga's even been given the nickname "Fap Note". And you have to admit that he has the same cynicalness as Light.
His catchphrase should be "Just as fapped!"
But he is very similar to Light. That's one of the great things about it, having someone so devious like that in a retarded and funny situation like beating off in a school bathroom.
Quote from Klapzi
The cool part is that I never get tired of being deceived
Quote from tactics
Just because someone's head was chopped off doesn't mean they're dead. That's just silly.