Why Did the Photo Lab Crop My Image?
If your printed photos look different from the version on your computer, the culprit may not be the lab.
On most DSLRs, an image straight out of the camera appears as a rectangle due to the 2:3 aspect ratio. When enlarged, this translates to an 8x12 print. This creates an issue for those who wish to make a standard 8x10 print. Your image is essentially too large to fit on the paper. As such, the lab has no choice but to cut two inches off of the photo. Those two inches may very well be part of your subject's head, making for undesirable results.
The solution: If you are interested in making 8x10 or 16x20 prints, shoot a bit loose, leaving several inches of empty space around your subject. When the lab crops to your desired print size, they won't have to cut into your subject.