That's because the tiling tips here--bathroom and kitchen, mainly--are meant to be quickies that you can absorb in an instant. Some are intuitive; others not so intuitive (and one is an outright rant).
In the ledge shown in this image, the tiler committed one major boo-boo. Instead of extending the horizontal window ledge tile all the way and having it cover up the edge of the vertical wall tile, the tiler has done the exact opposite.
This means:
- Yet another highly visible seam.
- Making the edge of a tile more obvious.
- Subjecting the tilework to more wear and tear.
