Yes, you can see the difference before you sharpen too much. But you should also realize that proper sharpening depends upon what you want to do with the image. The "correct" setting is usually different for display viewing vs. printing. Sometimes what looks ugly on the screen is fine when printed.
The camera always has a default sharpening. Even if you use RAW, that default sharpening is what you see on the preview jpeg, which is displayed if you look at the image in the camera. You can set it to zero, but that doesn't mean "no sharpening", just "as little as possible". Different cameras interpret the same setting differently. Traditionally, Canon have done it so that the entry level cameras (650 D) sharpening setting of 0 (least) is about equivalent to a 1D-series being set at 7 (most). Intermediate cameras are in between.
This is because people buying the cheapest cameras usually want a brilliant image out of camera, but those buying the top class cameras are often more interested in having a soft image to start with, so they can apply whatever sharpening they like. But softening an already sharpened image is much more difficult.