You're not wrong! You don't have to go 100 miles though, when I was a kid my parents moved to a new town just 10 miles away from where we lived before and I couldn't believe how different the accent was, I could barely understand people who spoke with the broadest accents.
It's levelling out now with the ease of travelling, after all the streets in the UK are no longer cobbled and you can be 100 miles away in less than 2 hours, so people mix more than they used to even 10 years ago, and TV has flattened out a lot of local dialects as well, but you can still hear different accents from 25 miles apart.
I used to go to the US a lot on business and once had trouble getting a glass of wine in Palo Alto. I asked for a glass of Merlot (pronounced Mer-loh) and the barman simply didn't know what I wanted even after 3 or 4 attempts, until a guy next to me at the bar said "I believe he wants a glass of Mu-loooow"
When I came up to Newcastle I asked for a Vodka and Coke at a bar. The barman was like "what...what do you want. Vodka and what?" He was taking the piss out me for pronouncing coke with the softer O sound. "We have Courke (this is the closest i can get to writing down how geordies say coke) not [posh accent]Coke[/posh accent].


