I'm not sure that folks are really answering the question that was asked. I mean, OK, maybe you were not really expecting to be completely blown away by Paris or Venice or Florence, and you were...but should that really have been a surprise? These are awfully famous places and their appeal is pretty well known.
I'll offer a few places that actually, you know, surprised me at how awesome they were...and that could not have been easily predicted by most others.
Latvia. Yeah, Latvia. Riga especially, but honestly, pretty much all the places we went in Latvia far, far exceeded my expectations. I went in not knowing much about the place, and it charmed the heck out of me at every turn. I told people I was going to Latvia, most asked "um, where?", some laughed and said "come on, you're kidding". So I had some doubts myself.
Sardinia. One of the most beautiful places I've ever been. Cagliari especially, but pretty much every day and every place we poked around left me gobsmacked. It just looked good on the map. It's Italy, it's an island surrounded by the sea, it's where Russian oligarchs and corrupt politicians love to hang out. It's Italy. It's named after a fish, I figured at worst there would be decent food. It turned out to be "pinch-me-this-can't-be-real" good.
Hokkaido. Japan's large northern island. We kind of threw a dart, shrugged, and said "sure, why not?" We kept just stumbling into one stunning thing/experience at every turn. We had similar experiences in Kyushu (Japan's large southern island). Given how much we had loved Hokkaido and our previous trips to Japan (and how much my wife kept telling me how cool Kyushu would be), I went in to the Kyushu trip with high expectations - and was still blown away.
[Deleted.] Sorry, locals made me promise not to tell people about [deleted]. I've tried to honor their request. My wife had never heard of [deleted], couldn't find it on a map and went there entirely on her blind faith in my choices, and my telling her I really thought it might be cool and we should take a chance on this place. She now constantly talks about that as our best trip ever and compares every other trip to it. I'm forever looking to replicate that discovery.
The lessons I've learned: Even though I'm a cynic, famous places like Venice, Amalfi, Edinburgh, and Strasbourg quickly won my heart, and I probably should have seen that coming even as I rolled my eyes at what others had told me about their experiences there. But places like Bonifacio, Saaremaa, Koh Lipe, Ait Benhaddou, Rebun, Xwejni Bay, Mykines, Misool, and Mandalay...those places far, far exceeded my expectations, worked their magic and completely blew me away.
Seeking out places that I had never heard of, and never expected would appeal to me, was the big lightbulb-over-my-head take-away. Of course, there's no place like Rome. But there are a thousand other awesome and lovable places waiting to be discovered (and still remarkably crowd-free) that any of us can find and experience, if you are willing to do a little digging and take a few chances. And THAT was the best and most surprising and most delightful thing I've found.
YMMV. And there's nothing wrong with loving London or Paris, too.