Let's suppose you own an online advertising platform and someone is running ads with a daily budget of $2.00. A week ago your systems showed this advertiser's ad to one of the advertiser's friends, even though that friend is not in the targeted group that is supposed to be shown the ad. Today your systems showed the ad to the advertiser themselves, despite both not being in the targeted group and being the person running the ad (which your systems are intimately aware of as they choose what ads to show).
Since your 'fictional' ad platform allows an advertiser to target only specific groups of people, showing the ad to people outside of the targeted group is a failure; you didn't do what you told your customer you would do, and you are charging them anyway.
What will you do to make things right with this $2-a-day customer? How quickly will you address their concerns? What's the return on investment in a quick and complete response to this customer?
You might think with the $2-a-day budget the advertiser doesn't matter to your bottom line. You would be wrong. The company the advertiser works for spends millions on online ads. Millions. Fail them, lose millions. Please them, and your return on investment is millions.
In fact the relatively small unit the advertiser works for alone spends around 3.6 million dollars a year on online ads, or about $10,000-a-day. The advertiser is evaluating your ad platform for possible future advertising for their business unit (that $3.6 million a year).
The $2-a-day spend is a test, a test you are failing since your systems aren't following the targeting rules the advertiser set up. If you don't explain yourself, and quickly, you lose not only the $2-a-day, but you'll likely see no part of the $3.6 million a year. Plus the advertiser will advise other business units in the company of your failure as well.
If you let your product look unreliable, or uncontrollable, an entire fortune 500's online ad spend is at risk. There are literally millions at risk if you fail to address why you showed ads to people this $2-a-day advertiser didn't target. Many think making your customer service effective even for the customers spending very little money with you isn't worth the money.
Turns out you can't afford not to delight every customer. Disappoint the customer who spends little with you, and best case they tell a friend, perhaps online on a blog or in a twitter for all to see when searching for you online. Worst case you lose millions.
As you may have guessed, this 'fictitious' ad platform example is not fictitious at all, it is very real and happening as I type this. Time will tell how it turns out for them.