I hated writing as a kid. I think part of the problem was that my thoughts were much faster than my pen, so I by default wrote as fast as I could. If I tried to write more legibly, my writing would still look poor compared to many others, and I'd have to slow to a fraction of the speed, so why bother? For instance, whenever I have to write my email address on a form (you know, it has to be perfectly legible or you won't receive your email), and half the letters still look like trash.