Even when the phone app does work the rotation animation and the wake up process of the n900 making it a pain to answer or reject a call.

Its almost impossible to fast answer a phonecall and need to wait atleast 5 to 10 seconds before the phone becomes responsive. if you touch the screen before this time or when you accidentally tilt the phone a little the animation starts a second and third time (portrait, landscape, portrait) then it will take another 5 seconds before you can answer. this is one the stupidest thing nokia ever made! by far!!! it just doesnt work!