Everyone thinks not testing staging environments. No sugarcoating this: what server location reveals about speed
https://bizzmarkblog.com/staging-matters-why-choosing-shared-hosting-for-every-client-site-is-a-shortcut-that-breaks-things/
If you run web services and your staging environment lives in a closet called "dev-us-east-1," you are making a bet with your users' patience. Most teams skip realistic staging tests because it's cheaper and faster