On the evil inclination... There are 7 names for the evil inclination, and the Gemara goes through each if the seven, where and who called it what. Plus, a "sipur aggadah" about Abaye and the yetzer hara. Alsi, more on the yetzer hara, that evil inclination: according to this Gemara, God regrets creating 4 things. Given how often the perfection of creation is discussed, the notion that creation is not perfect is an interesting approach in the Gemara. Plus, humanity seems to have been designed to sin.