Tourism is a highly taxed industry
Global standardization has produced less unique locales.
Tourism and travel are highly dependent on the cost of fuel
Security
Foreign laws
Safety, especially in urban areas
Political conditions
and lastly assumptions from other people, if your from a certain country or certain place people can start to assume things and sometimes it can be taken too far, especially if your culture only allows certain things you can wear or you speak another native language sometimes just people assuming the wrong or expecting something bad to happen can ruin the best of things