Dressed Fence - Toe-nailed

This picture, taken from the back looking forward, basically shows the difference in fence grade, or flow of the fence.

You will notice in the fence on the left, "Theirs", the tops of the post heights vary, bouncing up and down. On the fence to the right, their is a nice steady flow to the tops of the fence.

Now while a steady flow is not always obtainable due to grade conditions, this is clearly a case where "Their" installer did not know how to manage the grade or did not care to manage the grade properly.