The normal world:
Customer: "Hello, I need a hammer, pincers and a box of nails!"
Shopkeep: "Sure thing, here you go, have a nice day."
The software world:
Customer: "Hello, I need a hammer!"
Me: "Sure thing, here you go."
Customer: ... *keeps looking at me expectantly*
Me: "...would there be anything else?"
Customer: "You haven't given me the nails!"
Me: "Sorry, you didn't mention that you needed any nails. Let me just fetch those..."
Customer: "Well, I can't very well use a hammer without nails, so it really goes without saying that I need them."
Me: "Well, I just assumed you already had nails. Here you go!"
Customer *leaves chuckling "ha, yeah right, already had nails, like, who would just have nails lying around. Bloody bugger even put them on the bill separately..."
A few hours later, the phone rings.
Customer: "The Hammer you sold me is broken! It doesn't have pincers!"
Me: " ... "
Well, almost my reality. I would just apply the following patch there:
Customer: "Hello, I need a hammer!"
Me: "Sure thing, here you go. Do you have nails available? I can also recommend you to buy a pincer, we have it as special offer in our store right now."
Customer: "I should already have nails, thank you. And I'll look for a free alternative for a pincer."
Me: "OK, your choice."
A few hours later:
*phone* "You didn't tell me that this hammer requires nails and not screws."
"I thought you have nails. Do you want to order some?"
"I want them for free, that is a defect."
"Well, I'll have to talk with my manager about that defect. We'll call you back."
A few hours later:
"Your boss and my manager just agreed to make a follow-up contract for the nails, he understands that this can't be a defect if you did not order it. Do you still want no pincer?"
"No, I am looking for a free alternative."
A few days later:
"All my nails are broken - you must fix this, that is warranty."
"Its not. You just need a pincer."
"I don't need that expensive tool. My other supplier tried using a one cent coin, but your nails are faulty, he can't get them out."
"A coin is the wrong tool for the task, didn't he tell you? A pincer is all you need."
"A coin would be perfectly fine if you would have sold me coin compatible nails."
"You did not specify this and there are no coin compatible nails available. We would need to customize them for you."
"Forget it. Fix the nails ASAP! If you are unable to make coin compatible nails, I'll cancel the whole contract and let your competitors have it."
"Good luck, do you have their contact data or should we recommend our favorite rivals to you?"
*hangs up*
A few weeks later, pincers are enterprise standard.
A few years later, the customer will be forced to use pincers because the safety exception for using coins expired.