Well, as the OP, I tend to think of the thread as comments on the original topic;
Any kind of preface to a diatribe or fulmination looks off kilter, out of place as we lack the means within the forum to branch.
It's like butting in on someone elses input with something completely unrelated, thus sending the message that your thoughts, ideas or input is more important.
Sometimes a few posts happen, it's the way that new topics are born. Inflexibility breeds stagnation, but to constantly ***** something into the long grass either willfully or otherwise could be seen as incredibly disrespectful.
But what do I know? ;)