This is an excerpt from an article, "The Moving Finger Writes -- But Who Can Read It?" by Robert O'Brien that appeared in the Saturday Review in 1959:
In Washington, D.C., a truck driver misread a carelessly formed "4" for a "7" in a handwritten order, and pumped 285 gallons of fuel oil through a disconnected intake -- into a basement of the wrong house. In Connecticut, a housewife dashed off a note asking the milkman to leave three quarts of chocolate milk. The next morning, neatly stacked at the back door, were eight cartons of cottage cheese. In a New England city, a man stepped up to a bank teller's window and shoved a note under the wicket. In bold scratchwork it said, "wug I thiire a www cxzllmnhad!" The jittery teller kicked his alarm button, bells clanged, police converged on the bank and nabbed the man.They discovered that he was a respectable businessman with laryngitis. What the note said was "May I have a new checkbook?"
Bad handwriting doesn't always have results this bizarre. Still, illegibility on a national scale piles up astonishing statistics. An estimated million letters -- each one, without a doubt, of importance to someone -- wound up as "dead letters' in U.S. Post Offices last year because poorly written names or numerals made delivery impossible.
Bad handwriting also has ways of playing hob with our private lives. We boast the highest literacy rate in history, yet some of us can't make out our wives' shopping lists, our children's homework papers or what the waiter scribbles on our dinner checks. I have friends whose penmanship resembles seismograph recordings of the San Francisco earthquake.
Whenever I hear from them I can't help remembering what Thomas Bailey Aldrich once wrote a professor in reply to the professor's totally illegible letter: "It was very pleasant to me to get a letter from you the other day. Perhaps I should have found it pleasanter if I had been able to decipher it. I don't think that I mastered anything beyond the date (which I knew) and the signature (which I guessed at). There's a singular and perpetual charm in a letter of yours; it never grows old, it never loses its novelty. . . . Other letters are read and thrown away and forgotten, but yours are kept forever -- unread. One of them will last a reasonable man a lifetime."
Editors, of course, are notoriously poor handwriters. Horace Greeley's script, according to a contemporary, resembled "the tracks of a drunken hen."