I thought that the numeric keypad "+" key felt a bit weird. If you press it, it doesnt go down like the other keys, its as if there is something underneath it on the right hand side stopping it from going down all the way. upon closer inspection, it is a manufacturing fault and part of the plastic membrane isnt sat right and creased under the key. I presume this is covered under warranty but as I got it with my iMac, what do i do? just walk into an apple shop with my imac serial number?