Sharp as a doughnut and other similes

[Roguepiano]

The words "sharp", "dull" and "smooth" are used frequently on this site. It occurred to me that those words in themselves are insufficient to describe the degree of sharpness and smoothness that we are talking about here. We could use some more descriptive language to refer to these concepts.

To that end, how about a "sharp", "dull" and "smooth" simile thread? (extra points for humorous ones)

The first one that comes to mind is "sharp as a razor" but when you are talking about razors, that phrase is just about meaningless.

Here are a few that I could think of:

That razor was as sharp as a doughnut.
That razor was sharp as a slab of 5 year old cheddar.

That razor was dull as a wedding speech. (credit to Obie)
That razor was dull as a shag rug.

And perhaps something other than baby butt smooth… (I realize I may be treading on hallowed ground here.)

After that shave my face as smooth as a Ken Doll.
After that shave my face as smooth as a marble column.
After my first SR shave my face about as smooth as a stucco bathtub.

You get the idea. Do you guys have any ideas?