My two big issues was that gravity was working against my fingers to keep them on the buttons, and also the side of my palm would rub along the surface if the desk as I used it. I had to hold my hand up and in position the whole time instead of just laying it on there like a normal mouse, got hand cramps after one day of using it. Thankfully I was just borrowing it from a coworker who also hated it so I had no investment lol.