Almost everyone visiting Portugal stays within thirty kilometres of the Atlantic. The interior is emptier, cheaper and where the country's oldest places are.
Most of Iceland's visitors see the same 300 kilometres. The Westfjords and the east get a fraction of the traffic for arguably better landscape.
The fjords are best seen from the local ferries that Norwegians actually use, which cost a fraction of the tourist boats and go to better places.
Rome punishes the wrong shoes and turns you away from its best buildings for the wrong clothes, and both are easy to get right.
Barcelona's famous sights take two days. What makes a longer stay worthwhile is the parts of the city that are not on the Gaudí route at all.
Ninety percent of visitors to France see Paris, Provence and the Riviera. The regions between them are emptier, cheaper and frequently better.