One of the best things about the Internet is how it has taken all the legwork out of shopping.
Without so much as having to put on shoes, you can compare prices, read product reviews, monitor sales and chat with stylists.
To buy something and have it delivered to your doorstep, you barely have to lift a finger - just enough for a few mouse clicks.
Sometimes you don't even have to do that much. Gift websites that record important dates and send flowers on your behalf ensure that you never miss a birthday or anniversary, through virtually no effort of your own.
Retailers can also "remember" your regular purchases - such as cat food or laundry detergent - and allow you to schedule automatic deliveries every month.
Such recurring services are possible because you can - and indeed are encouraged to - leave multiple billing and shipping addresses, as well as all your credit card information, on file with the retailer.
And that is also one of the biggest dangers of the Internet: that it is taking a lot of the brainwork out of shopping. Online short cuts allow consumers not just to save energy in choosing what to buy and when to buy it, but also to bypass their usual mental safeguards each time they make a purchase.
That would be fine if all retailers were trustworthy and all transactions went smoothly. But in the real world, the convenience of recurring services comes at a potential cost - which I discovered recently on my credit card bill.
An international financial newspaper had charged me $270, a fee I had not expected. Yes, I had taken out an annual subscription to the paper, but that was in September last year, and I had not agreed to renew the subscription.
In fact, I had planned to cancel the subscription when I received the renewal reminder, which I expected as a standard procedure from any recurring service.
Perhaps the reminder e-mail had gone into my spam folder. I duly sifted through messages offering to make me a millionaire while working from home or granting exclusive access to private photo galleries, but I couldn't find any e-mail from the newspaper.
I then logged on to my account on the newspaper's website, which is when I found something even more disturbing.
The credit card that I had used to pay for my subscription to the newspaper had actually expired in December. I had renewed the card then, which meant the cardholder name and the card number remained the same - but the expiry date and CVV security code on the back of the card had changed.
And yet the newspaper had somehow been able to charge another year's subscription fee to my - expired - credit card.
I immediately sent e-mail messages to the newspaper in question as well as my credit card issuing bank to ask for an explanation. Their replies raised even more questions.
The newspaper's service representative - let's call him Mr M - told me, rather glibly, that the company recognises "how important reliable access to our world-class content is to our subscribers and we make every effort to provide a continuity of service".
This apparently includes participating in schemes provided by Visa and MasterCard "for the updating of card details wherever possible so that in a continuous billing model such as ours we can avoid unwanted breaks of service".
Mr M added: "A number of attempts are then made to process a payment should one fail initially and often this is successful."
Put simply, merchants such as the newspaper are tying up with credit card issuers to "update" the details of customers' expired cards - so they can go right on charging them.
How do they know what to update? My bank shed more light on this practice.