Check out the above painting by Camille Pissarro and look closely at how much detail is added. Notice how when you focus on certain areas of the painting, there is really not much detail at all, just seemingly random strokes of color. But it all comes together in beautiful harmony.

Also, notice how little detail is used to render the person in the bottom right. Without the rest of the scene, it would probably not resemble anything.

Pissarro has used simplification in this case, to draw attention away from the shadowed foreground and bring the viewer through the trees into the high-key background. Too much detail in the foreground would probably make the painting seem too active.