Why does everything I touch break?

I'm almost proud of myself; today I crashed a Lowe's self checkout kiosk.  I had returned a duplicate Christmas gift, which resulted in a store-credit gift card, and we had a $79 prepaid Visa/Store credit gift card that was a rebate for the delivery cost on our Dishwasher & Refrigerator.  So we went to self check-out, as usual, because I don't mind chipping in on their labor costs to save some time.

We had a few large items, like trash cans, so the cashier was helpful enough to scan the big stuff.  When it came time to pay, I used the store-credit/gift card first, and all went as planned.  Then I tried to use the prepaid/rebate card as a Visa (since it had the Visa logo and a signature panel, and CVV code).  When we swiped it, the chaos began.  It declined the card, then prompted that we'd need assistance.  So the cashier took the card, and tried to run it.  That failed, because apparently you have to tell the machine how much the card is worth.  (I suggested $1 Million, or $Texas, but she refused both).  So we tried entering $79, and after giving ZIP code, cardholder name, and several other bits of not-necessary-but-whatever information, it tried running the card again, and failed.  So the cashier gets the lead, who tries a few other things, none of which work.  They even started to cancel it and ring us up normally, but since we'd already surrendered the gift card to the self-checkout box, that wouldn't work either.  So they said here, try it again as a credit.  I pushed the credit button, and everything ground to a halt.  No buttons on the touch screen, no indication, even the cashier's screen froze at one point.  I heard the lead on the phone with tech support, "okay, it's saying enter username and password."  My inner geek couldn't resist any longer, and I watched as she activated the hidden secret button, and up popped a familiar Windows UI, and some Lowe's-branded "Ctrl+Alt+Delete" type screen, followed by a reboot.

Finally, they concluded that they would ring us up normally, but discount several items equal to the amount of the gift card, then use the prepaid card as "usual".  In the end, that worked, and rather than having to pay out-of-pocket for the $1.01 something difference, we ended up with a balance of about $3 on the prepaid card that we chalked up to a "convenience discount" for spending as long at the register as we did in the store.  And as for the prepaid card, I doubt we'll even try to use it after that experience!