Tiny games about blobs who can’t agree what anything is called. Every one of them is somebody’s Tuesday.
Every game you just played is one real problem, wearing a silly hat. The same thing defined a hundred and forty-eight times so nobody can tell which is the real one. A reader that throws away a whole message over one field it didn’t recognise. Two systems that both say “3” and mean different things. A change that can only ship if everyone moves at once, including the client nobody remembers building. A quick copy that felt free and wasn’t. Eighteen products on the shelf that were only ever two things underneath. A block built beautifully, next to five others it never met.
None of them are bugs, and none of them get fixed by working harder or testing more. They get fixed earlier than that — by treating the shape of the thing as something you agree on purpose, once, before anyone builds on it.
That is all a target architecture is: the joins drawn on the edges of your block before you start, so the thing you build meets what is already there. Not a plan that tells you what to build. Just the bit you were never going to be able to see from inside.