How spies communicate, or why algorithms are needed

One of the questions I quite often hear from novice developers goes something like this:
‘Why do I need algorithms at all?’
Why bother with bitwise operations? Why think about algorithmic complexity? Why do they give us all these strange problems in job interviews, when in my actual job I’ll just be writing APIs, passing JSON from one service to another and integrating yet another library?
It’s a perfectly valid question, I must say, especially when you’re once again faced with a problem that asks you to shift something three bits to the right, apply a 0xFE mask, and then, for some reason, be pleased with the result.
Instead of abstract musings on how algorithms develop one’s thinking, I suggest we take a look at a perfectly ordinary image.