What's more important on mail- the city or the zip code?

Long story short, I ordered a book but accidentally gave the wrong city. The zip code and address is correct, will it be returned to sender? Or will USPS go by the zip code?|||Zip code. You really don't even need the city on there since each city has it's own zip code. Those things are read by machines when sorted. The machines only read the zip code. The city is on there only if you mess up the zip code.|||I believe the Zip is more important. Hopefully, the mail folks will look at the address and find it under the zip and not the city. But then again, USPS workers are kind of lazy... lol|||they will use zip code and they will also use your telephone number as a back check, so don't worry.|||The zip code is most important.