I live in the middle of a major UK city, which is one of the most visited tourist destinations in the UK (if not the world). There are massive gaps of mobile coverage in the city - 5G is spotty at best, and it regularly falls back to much older protocols in the city. There are dead zones where you can literally walk 6 ft and drop to 0 coverage, and walk another 6ft and be on full blown 5G. Apps and sites like uber, twitter, Reddit, instagram all handle these awfully.