My (manuscript) handwriting has been charitably referred to as "chicken scratch" on occasion, while my cursive simply causes people's heads to explode once they figure out that it's supposed to be actual writing.
My favorite times are when someone takes a sheet of paper covered with my notes, flips it completely over, and they holds it up to a light in a vain attempt to make out some of the letters on it. It probably doesn't help that I used to use my own arcane system of shorthand, either ~_~
When I REALLY need to, I can write things reasonably neatly, but my writing speed slows to about 1/5 of normal speed -- I reserve this for times when there is no time restriction whatsoever on my scribbles.