For example, this image has a person in it, but it's too subtle. The resultant image is .... weak.
Adding a stronger human element helps.
Here's another where a human element provides depth and balance.
And one more.
Sometimes it's all about the people.
And sometimes the people look very natural.
Other times, not so much.
The women above are doing their best to blend in with the local color, but their fresh-bought saris are still creased from the packaging. She deserves credit for the perfect color matching though: sari, bracelets, phone, camera, purse...
These women stand out because they look so unnatural.
These guys, however, stand out because they look just right.