[hermitdev]

This is basically the Mythical Man Month in a few lines.

You once wrote something specific, and it was great. Then you had to write a second thing, and you remember things from the first, so why not make it more general for the inevitable 3rd, 4th, 5th to come? And, then, you fail to deliver the 2nd.

[arthurjj]

I don't have my copy handy, but I believe that's actually the second system effect

[hermitdev]

You're correct, but it is also described in the book, "Mythical Man Month".