You can just tell the AI to not be warm and it will remember. My ChatGPT used the phrase "turn it up to eleven" and I told it never to speak in that manner ever again and its been very robotic ever since.
If so, my understanding for these preambles is that they need a seed to complete their answer.
Also I wonder if it could be a side effect of all the supposed alignment efforts that go into training. If you train in a bunch of negative reinforcement samples where the model says something like “sorry I can’t do that” maybe it pushes the model to say things like “sure I’ll do that” in positive cases too?
Disclaimer that I am just yapping
Long story short it took me a while to figure out why I had to keep telling it to keep going and the story was so straightforward.