What are some of your experiences with this?

I can say I've had good and bad - I've wondered through cities with no direction and found -- nothing, two that come to mind are Paris and Barcelona. I'm sure there is interesting stuff to be found here and there but mostly, outside of the main attractions, I found the rest not much more interesting than American suburbia. Yes, I'm glad I saw it to basically see that "life is life". There's the interesting coast, or the restaurant row that's already on the tourist map, then there's the living areas where every block or two there's a convenience store, another non-descript cafe, a hair salon, etc... Maybe once in a while something sticks out but mostly not.

To be clear, I found both cities amazing. But, the "this city is amazing" parts are the parts listed as must visit. The "get lost parts" less so, with a few exceptions.

I've had more luck doing things further down the list. On 3rd or 4th visit, I'm not doing the top 10 most popular things. I'm down on 40th or 50th or 100th.