Robert Neville writes:
Hand cash over - walk out. If you can do that faster with a credit
card then I'd be interesting in hearing your technique.

Except it doesn't work that way. What usually happens is that
customer stands there with a blank look until all items are rung and
total is available. Customer then proceeds to fumble through
wallet/purse, looking for correct number of notes, and that last
coin or two that they know is there somewhere. Cashier eventually
takes cash, recounts it and enters amount tendered in
register. Cashier then spends 30 seconds trying to figure the
appropriate number of each bill and coin to make up the amount shown
on the display. Cashier hands change back to customer who proceeds
to count it, eventually giving up on the higher math involved and
drops change on floor. Eventually customer collects things and self
and moves out of the way.

Contrast that with customer paying by card, who within certain
parameters, doesn't care what the total is, pulls card out while
cashier is ringing order and hands card to cashier as soon as order
is totaled. Cashier swipes card, hands card and receipt back to
customer who proceeds on his or her way.

Er, if it's the _same_ customer we're talking about, it's not going to
work that way. He's going to stand there with a blank look until all
items are rung and total is available, then slowwwwly pull out his
wallet, and fumble around looking for his card (even though he used it
5 minutes earlier), then drop it on the floor, forget his PIN, call
his wife and ask her, type it in wrong several times, and then argue
with the cashier for 30 minutes after his card is rejected. If it
_isn't_ rejected, he'll stand there blocking the line while he
slowwwwly fumbles around putting his card back in his wallet, dropping
the wallet on the ground, slowwwwly picking it up... and _then_ start
collecting his purchases...

-miles

--
The secret to creativity is knowing how to hide your sources.
--Albert Einstein