It's not like you're going to die if you don't get the book you want in 2 days, or even 3-7 business days. (Not that I buy physical books anymore typically, but it applies to other items)
People have just grown very impatient over time. I found myself getting annoyed that I wasn't receiving some items in 1 day (in Korea), until I reflected on what I actually was getting annoyed over.
Personally I find myself buying things on amazon or gmarket simply to avoid having to drive to the store.