In my wallet is the cutest tiny little ink-pen, the kind you twist for the nib to come out, and it slips into the fold where the billfold folds, and the little hook-clasp at the end catches onto the flap where the money goes, and there it nestles, nook-tucked, like a lucky charm. You'd never know it was in there.
Also in my wallet, I carry a small stock of business cards. If we ever meet, and you ask me if I have a business card, and a guilty look flashes across my face and I freeze and can't seem to answer, it is because I don't know how to say "Yes, but they're all covered closely with cramped, indecipherable writing of band names, song ideas, dialogue snippets, book titles, and quotes, and I've forgotten or neglected to take the used ones, put them in the 'later transcription' bin, and replace them with fresh stock for future use and/or god-forbid giving them out to people."
HINT: WRITE ON THE FRONT SIDE FIRST. You will then not fail to notice "oh, sorry - this business card of mine has been desecrated by some vandal! Let's see if I can fish out another one, an undesecrated one."
But if you write on the back first, because it so smooth and white and exciting, so blank, so ready for the pen - I can understand the appeal of that back-first action, but it's risky. You can't guarantee that days from now somebody won't end up turning over the business card you gave them days ago, only to find a series of cryptic notes and not-too-flattering-to-you phrases and statements.
For example, written down the left border (narrow axis):
Fun City Dump Truck
the Dog Owners
Squandered Talent Award
Jihad For Thor!
Freud's Smokin Penis
(something completely, obliteratedly crossed out into a long, pushed-in black rectangle)
the Partly Favors
Then coming up from the opposite side of the card, quotes - but quotes of WHOM? Only 1 is attributed!
"I am not myself for your benefit!"
"god is omniscient, but can't take a hint"
"There's no mystique with ourselves, is there?" - Mel
"I've got every place to be and only my lifetime to make it there"
And then finally, written upside-down along the top border (long axis): I wish to purchase a peerage of considerable lineage and dignity.
The worst part is, you'll be kicking yourself when you realize you can't get those back, because you have no idea who you gave them to.