I have bad handwriting (
ironic, since I write for a living.)
This is partly because, when I inscribe words upon the universe, I usually type at great speed. When I filled in the one-size-fits-many form for my couple of years of employment by the Dark Lord (never met the man himself; saw his son a couple of times), under "typing speed", I wrote "fast".
I just don't write with a pen or pencil very often, so I'm out of practice.
My lousy writing is mainly natural, though. The "Modified Cursive" handwriting they taught me in school never really took. My running writing always sucked, even when I was in school and had to do it all the time.
These days, when I write, I print - though if I do a running-writing lower-case "p", I still do the Modified Cursive version that looks like an "h" with a descender. But I digress.
The point of this largely unnecessary writeup is that bad handwriting is not necessarily illegible handwriting.
My mother is an English teacher. For quite a few years now, she's been teaching at a fancy selective girls' school. She has to deal with three basic kinds of handwriting while enduring the unending punishment of marking.
1: Legible and good-looking. Not necessarily Queen Elizabeth the Second's Signature, but pleasing to the eye, and thoroughly readable.
2: Legible but ugly.
3: Illegible.
Illegible handwriting often looks quite good, at a glance. The canonical example is "a wavy line with a few dots above it". My mum's school, like Australian selective schools in general, has a lot of students from pushy Asian families, disturbingly often on the fast track to a thrilling career in accountancy. These kids typically do well at any subject that isn't "the Humanities" (not a term you hear often in Australia). They're not stupid; they're just not from a native English-speaking environment, and English is a total bastard of a language to learn, so it's hardly surprising that they don't do too well in subjects based around it.
These kids' writing is most likely to be attractive yet hard to read.
My writing isn't like that. It's in category 2. Several people have, without conferring, described it as looking like the writing of a small child.
I am very slightly embarrassed about this. When disposing of used shopping lists on the way back from the supermarket, I wonder if anybody will see them and think they've been written by some latchkey child sent to get bread by his or her inebriated parent, who intends to use the loaf to filter brake fluid.