It's hard to tune heavily tuned code. - Larry Wall

And I don't like doing silly things (except on purpose).

It's there as a sop to former Ada programmers.

People understand instinctively that the best way for computer programs to communicate with each other is for each of the them to be strict in what they emit, and liberal in what they accept. The odd thing is that people themselves are not willing to be strict in how they speak, and liberal in how they listen. You'd think that would also be obvious. Instead, we're taught to express ourselves.