Yeah, what the auto does is: "The Light-Meter is telling me we need these Parameters to make this Zone exposed in the middle of the Histogram, and to hell with everything else!"
Motion blur, cam-shake blur, depth of field and sometimes grainy noise are...random. Depending on external conditions. Of which the camera can measure only available light and contrast. Contrast determines/helps the autofocus. Which we all use most of the time. In DSLRs, we just have the choice of specific points of the frame where we want the Auto to find contrast and thus, focus.