Probably, my lines don't look like that. It could be, too, that you aren't quite used to how you need to move the mouse with that wrist position. With a regular mouse, you can make a vertical line by clawing the mouse and flexing your wrist. With the 6000, you need to move your whole arm. If you try to "claw and flex" a vertical line with the 6000, you will get a diagonal line moving from right to left, top to bottom. I still do this from time to time, but it does take a little while to relearn the muscle memory.