Maybe Google Wave won't be as revolutionary as some think, but calling Google arrogant for coming up with new stuff seems just ranting for the sake of ranting.
callus: A callus (or callosity) is an especially toughened area of skin which has become relatively thick and hard as a response to repeated contact
callous: emotionally hardened; "a callous indifference to suffering"; "cold-blooded and indurate to public opinion"