I lived all over the world, including the Mid Atlantic, the South, California, New England and Colorado.
The worst thunderstorms are in Colorado, where the Rockies meet the Great Plains. That pushed the cloud tops higher than any place else in the USA.
BTW, European, Asian and Australian Thunderstorms are not as bad as North America. We are geographically in Storm Alley.
Another Azores, Portugal Bump to the Top!
You said that Colorado thunder storms are the worst. No way. North Georgia storms are much more severe.