Let’s imagine, for a moment, that you’ve been charged with the task of building a Robot. Let’s not worry about the Whys and Hows of this scenario, only that this is your job. You are going to build a Robot for Some Guy, and that’s pretty much all you need to know.
Oh, wait, one more thing. You’ve been told where to get the parts from. There’s Some Other Guy. He’s a pretty neat guy. You get along. You have shared interests. The problem is that this Other Guy is also providing parts for about nine or ten other people, so he’s not always able to get your parts straight away.
Now imagine that Some Guy, the same Some Guy who asked you to build the Robot, comes up to you to ask how his Robot is progressing. Well, you can’t answer him, can you? You don’t have the parts. It’s out of your control - Some Other Guy pretty much has the monopoly on Robot Parts, after all. It’s entirely out of your hands. You can learn how to build the parts yourself - that’s an option - but it’s going to take time. This Robot isn’t going to be finished any time soon. It’s annoying, but it’s out of your control and it can’t be helped.
“No,” said Some Guy. “You’re supposed to be building a Robot. Why aren’t you building a Robot? You should build me a Robot.”
So you explain, again, that you can’t get the parts. Some Guy doesn’t seem to care that you can’t get the parts. You’ve already got some of them, after all. He asked for a Robot. He should have a Robot. Where is his Robot?
It’s times like this, I’m sure you’ll agree, when you’ll wonder why you even bothered getting a job in Robot Construction.