Unfortunately, there doesn't seem to be a particularly good home for this question the way you've written it.
Normally, there is a distinction between a question being "on-topic" and a question being "a good question". Off-topic questions get closed, while bad on-topic questions just get downvoted.
With migrations, however, the bar is significantly higher. We don't want to migrate bad questions to other sites, even if they would, strictly speaking, be on-topic there. That gives the impression that we're just trying to "dump our garbage" on other sites. (Please don't take this as a personal affront -- this is merely the overall impression we're trying to avoid).
In your case, I think your major problem is you're asking too much:
So where does the phrase come from, and/or why is it I so many different movies?
That's two very different questions, and I think they are getting in the way of each other. Lets take them in reverse order, because it's easier:
The second question, by itself, would probably get closed as too-broad on this site. It's such a common English phrase, that it would be like asking "why do they say 'hello' or 'goodbye' so often in movies." I don't think you're going to find a good answer to that, other that the obvious fact that it has the meaning the writers want to convey -- which basically applies to everything you see in dialogue.
The first part, however, taken by itself, would probably make a semi-decent question on the English Stack Exchange. That part alone is a question asking for the origin or etymology of an English phrase. That seems to be like it would be on-topic over there. Unfortunately, as-is, we can't migrate your question because the other bit's still there.
My recommendation to you would be to let this question get closed -- by now, the revision history and downvotes would likely scare away any English:SE mod who saw M&TV trying to migrate it. At this point, it's probably a lost cause.
Instead, narrow your question to just the aspect of "origin of the phrase"; you can still use the movie quotes as reference for where you heard it, and in what context, but be sure to focus on the part that you're likely to get answered, namely, "where did this phrase originate?".
Caveat: I am not a regular on English:SE; I can't guarantee they'll like the question over there, but I think if you focus it and make it on-topic, that is your best chance to get an answer.