The beginning of Siheyuan starts with refusing to bring lunch boxes

A delivery boy from the 21st century accidentally traveled to a world full of birds in a courtyard. It happened to be the day when the Moral God PUA Sha Zhu brought lunch boxes to the Jia family. Lunch box? Wouldn't it be nice if I could eat it myself? Damn, I have a system, why would I eat a lunch box? A poor guy traveled through time and only had a system for daily necessities, so he just lived in this era honestly. There was no need to fight and kill, but he stayed away from widows, especially the black widow, who was the only female protagonist, and didn't raise a harem...