I absolutely hated Dubai, although to be fair I didn't expect to like it as its really not my kind of place. I was only there as ex-boyfriend was on a business trip for 5 days before we flew on to Kenya/Tanzania (which were amazing).
On the flip side though, I loved Las Vegas when we stopped there on a road trip from Phoenix to San Francisco. It was so kitsch and tacky it was hilarious, although 4 days there was enough.
I've travelled extensively in Latin America and spent periods living and working there and although it overall contains almost all of my favourite places in the world, there are also some truly grim and dangerous towns and cities there, particularly in Honduras, Guatemala and Nicaragua. Despite what people usually think, Colombia is stunning though, and the people are lovely.
My 'unexpectedly better' place is probably Bolivia - after spending a lot of time in Peru I thought it wouldn't compare. I was so wrong!
Bali is ok but I vastly preferred Lombok and the Gili Islands. I spent a month in Australia and found it enough but 3 months in New Zealand went by in a flash.
Anither place I was keen to leave was Zimbabwe, it felt seedy, unwelcoming and dangerous. Zambia, Malawi and Botswana are all amazing though, especially Botswana.
In the UK I never tire of Dartmoor, the beaches in Cornwall and the north coast of Northern Ireland.