No place has dramatically 'changed my mind' - but, universally, any initial twinges of doubt have given way to enjoyment. So, to that extent, everywhere stereotyped as in some way dodgy has proven not to be so and everywhere has exceeded expectations and driven the urge to extend boundaries - now viciously curtailed by Covid, of course. And time (and I dare say capacity to pay age/Covid-induced exorbitant travel insurance) is running out.
So, my motto has very firmly become: 'Put away your stereotypes - because they are wrong.' It's still hard to convince people, though.
I have found no problems everywhere I've been, with the 'people on the street' being friendly and just getting on with their lives. Treat people with the respect that you would like, and do in Rome as the Romans do, and there are unlikely to be problems. Of course, anyone can be unlucky and robbed - or king-hit by a drunk or druggie in the entertainment precincts of any city in Australia (probably the world epitome of such behaviour).
I like getting out into the hinterland of places, after a quick look at the main city or major cities and towns. Perhaps it's nicer there.
Some places people might baulk at: Sudan, many countries in SE Africa (S Africa, Zimbabwe, Kenya, Tanzania, Malawi, Tanzania), Rwanda (one of the cleanest places in the world - I kid you not), Namibia, Iran, Cuba, Oman, Ethiopia, Madagascar, the 5 'Stans, Chile, Argentina, Colombia, Ecuador, Mexico, India - the list goes on, I have never had a problem.
More to the point, they have all been eye-opening and mind-expanding - as, of course, have been the mainstream destinations in Europe, North America, Asia, Oceania.