Instruct: Classify Amazon reviews into positive or negative sentiment
Query: i dont know why i purchased this item

i'm really not satisfied with V400... the accelaration is terrible.. tracking is the worst part.. sometimes the pointer goes wherever it wants.. easily get confused.. clicking is so noisy.. programmable forward/backward buttons are not really programmable, i mean you cannot assign them whatever you want... they dont work even for volume up and down (if someone could do it pls share with me how to assign the volume control)...when you lift the mouse for a while and then put it back again, for a few seconds it doesnt recognize that it is on the ground again and it just wait still...all in all, i am really angry with logitech because they produce such a terrible and workless product...the best and the coolest thing is its design, but it is nothing either if it does not work!