thought while wielding a kitchen knife

Among the selections from the produce stand, corn (maize) probably holds the record for having the greatest amount, in the form that you bring it home from the grocer's, that's discarded rather than eaten.

But celery, if you chop it down to the traditional stalks, is a good second.

I suppose you could use the cut-off bits to make cream of celery soup, and in fact I've done that, but I don't have much use for this either.