Most don't know this, but what you think is wasabi you're putting on your finely sliced piece of sashami, or your delicately combined piece of nigiri, is actually horseradish with food colouring and wasabi flavoring. Real wasabi, if pre-grated for you, should have some fiber left in it, like when you grate ginger. Here in Japan, many of the smaller, more traditional restaurants will have real wasabi!! The above picture was from a local udon shop near my brother's place that serves all their udon with a fresh wasabi root and a grater. The flavor is definitely different, and better. Not as hot, but more mellow flavor. I haven't been there in over a year, but Shiro Sushi on Cambie in Vancouver used to use real wasabi. But there's nothing like grating it yourself!