The seven deadly sins include: pride, envy, wrath, sloth, greed, gluttony and lust.
It is also said in Zen Buddhism that sex is particularly harmful and makes people drunk, and this is the fundamental good for life and death.
But Xiao Xiao believes that lust is just the most primitive desire of human beings. It doesn't matter what is right or wrong, good or evil, it's just that you meet the person who needs the same thing at the time you need it, that's all.