The List Universe has a top ten list of evolutionary holdovers in modern humans. These are often vestigial and range anywhere from junk DNA (nonfunctional vitamin C genes)to the appendix and are interesting in that they truly show how cobbled together we really are.
Here is an interesting example:
The plantaris muscle is used by animals in gripping and manipulating objects with their feet - something you see with apes who seem to be able to use their feet as well as their hands. Humans have this muscle as well, but it is now so underdeveloped that it is often taken out by doctors when they need tissue for reconstruction in other parts of the body. The muscle is so unimportant to the human body that 9% of humans are now born without it.
Evolution works with what it has. This has often led those of us that believe in God to wonder why He has such an odd sense of humor.