Fans of the actor Tom Cruise are probably familiar with the phrase ‘show me the money’ – a totemic line from the 1996 movie Jerry Maguire.

You don’t need to have seen the film to get what the point of the line is; money talks, and the mess-that-bulls-leave-behind walks. The bottom line in all business transactions is the same wherever you are. But it also works as a reminder of the importance of following through on your commitments, of keeping your promises.

We all know talk is cheap and that’s because of the laws of supply and demand. Anyone can make promises, not everyone can keep them. Anyone can tell you how great they are, not everyone can prove it.

Nurturing relationships with customers used to be about offering great prices and unbeatable service. The advent of loyalty schemes saw a more systematic and data-driven approach taken to customer relationships. From Boots’ Advantage to the Tesco Clubcard, from Nectar to the relative newcomer of the myWaitrose card, retailers want to track what you buy so they can tie offers to purchasing habits.

>See also: Software considerations – should you go in-house?

But the value of these schemes has diminished in shoppers’ eyes, both figuratively and materially. Everyone offers a loyalty scheme, many people have enrolled in several competing schemes, and they still don’t routinely use their cards, meaning the data captured about their shopping habits is incomplete and the offers they are emailed fall short.

Too much noise, not enough signal. We’ve all started to switch off, to disengage from all but the most meaningful and relevant communications.

Although to an extent building great customer relationships will always be about the twin virtues of products and service, there is now a new kid on the loyalty block and this one is so profoundly connected to the business of keeping your promises that it can undermine all your other efforts at the drop of a hat. Or should that be at the drop of a parcel?

At an almost existential level, e-commerce is little more than a shuffling of pixels. You see something on a website, you click, you enter payment and delivery information and you have transacted.

No money was involved. No physical goods were present. And the only human being that had to participate in it all was you – and once the smart fridge of the future takes off even that will become a moot point.

Online shoppers are buying a promise. You are promising the item they have bought will be delivered in pristine condition and that it will arrive when they expect it.

But you already know all this.

>Related: Six tips to develop a high-growth mindset

It shouldn’t, therefore, come as much of a surprise to know the extent to which missed expectations, when it comes to the condition of the purchased goods and their delivery, is the new yardstick by which etailers are being judged. If you get it wrong you better have a good reason for getting it wrong, and you better be quick about putting things right.

Because, let’s face it, you’re unlikely to be the only game in town. In e-commerce, everyone is competing for customers from the same pool of shoppers, and their using all the same techniques as one another: emails, social, SEO, flash sales, loyalty schemes, advertising, PR, you name it.

If you can’t follow through, if you literally cannot deliver, you have broken the covenant that exists between buyer and seller in the online world.

There’s only one field of battle worth bothering with because everything else is now a hygiene factor. That field… the last mile.

If you can’t get it right there, your customer relationships may suffer irretrievably. It’s as simple as that.