This week, I finished eroding every last vestige of the bump on the 'J' key on my keyboard at work. So when I move my hand off the mouse and back to the keyboard, it's always interesting to see if I'll be typing actual words or random gibberish. The bump on the 'F' key went some time ago, but as I rarely move my left hand off the keyboard, it doesn't affect me too much.
There's also a gaping hole in the lower-left corner of the down-arrow key, because when I put my hands on the arrow cluster, I put my index, middle and annular fingers on the left-arrow, up-arrow and right-arrow keys, and I tuck my thumb under for the down-arrow, which means that my thumbnail rests on the corner of the key, and from less than a year's worth of use, has actually cut a groove into and through the wall of the key.
They just don't make keyboards like they used to. My first keyboard — a genuine IBM keyboard — was so heavy that I think the keys and case were actually cast iron. The keys made a satisfying CHUNK noise as they went down, and you could probably roll a Sherman tank over it without doing any damage.