In every other mouse the sensor is at the center of the body. On magic mouse the sensor is at the front under your fingers as you can see in the OP thumbnail.
That makes it very hard to adapt to when you're coming off of other mice. When you're moving the mouse you better not slightly rotate it out of habit and ergonomics because the cursor will move weird.
I really tried giving it a shot because I like apple gestures. They work fabulously well on the trackpad. The magic mouse is garbage in every category really.