Why geolocation based settings are bad
Just imagine travelling to Japan, having to look up some details about your trip, Google shows up in Japanese language. If you're lucky your phone has a translation service that can automatically translate websites. Or the website allows you to switch the language somewhere and you're able to identify the switch. Most websites have this switch at the bottom of the website. But some websites automatically load more content when reaching the end of the list which makes the language dropdown disappear while you're trying to switch the language.
Looking at most (99%) multi-language implementations, I am getting the impression that language detection and selection is implemented by developers who have never traveled to a foreign country. Therefore I'd like to appeal to everybody doing i18n to respect web-standards and use primarily the Accept-Language headers. Or at least make switching the preferred language easier.
P.S.: Sorry for typos (Android keyboard) and grammatical errors. Native German speaker here.