@ Dexter
Your points are not ill-concieved, and you are on to something but let me show you how I see things.
In the sense of your green-light scenario, no, I don't apply this view to everyday life. When it comes to bare-bones perception and expectation, I live as everyone else, this is true. The reason is that so far, all I have seen are things I expect (or mostly anyway), and as such, since it is my nature to try to preserve the status quo (whether that's a good idea or not), I try to survive with what I know, how I know. This doesn't make it anymore likely that what appears to be real is real though, all it means is that up till now it has served me well enough.
Also, you implied that total uncertainty about everything would lead to some kind of fear or incapacitation. Not so. What it is, is a humbling of my assumptions, that every time I draw a conclusion from something, that I may be laid low and proved wrong at any time. When it comes to everyday life, you're right, I can't very well go through that thought process every time I take an action, and I don't. Because of some factor in my brain or in my very consiousness, I am not built to have the capability to incoporate that into every last decision. My intelligence does not span that deeply, and it is proof how unnatural/unorthodox the belief is.
However, when arguing, or when attempting to explain to myself mysteries in my own life, whether they be strange phenomena or inexplicable actions by other people, my belief system does cross my mind and plays a large role. I usually draw first a conclusion that is consistent with the real world as I know it and would normally agree with, say, a secular humanist (just because this is the cutlture I live in), but then if it is of great importance to me I will deconstruct it further, imagining some other, "other-worldly" explanations. These forays always end the same way, with me thinking, "Well, I just can't know for sure one way or the other."
As a result, I either end up ignoring the mystery, because I cannot know, or operating as if the secular humanist explanation is true. This is not because I strictly AM a secular humanist, it is because most other I know are, and this is a middle ground that most people can accept for a basis of actions. Granted, none of that may matter, for countless reasons (i.e., no one else exists anyway), but as I said, I intellectually acknowledge the possibility of an infinity of scenarios, but live mostly as though I pretend to know the answer.
The big difference then, between me and this hypothetical secular humanist, is that I do not presume to tell anyone what I KNOW to be true. I never tell them about what science has PROVED. I make no assumptions about what we have discerned from the universe and never assume that what someone teaches me, ideologically, is correct. It makes for a good argumentational standpoint, one that is fresh and can bring new perspectives on old arguments. It also makes for a belief system that inspires not only universal skepticism but universal respect, because, as I said, though my perception (that which I remember anyway), as yet, has told me that secular humanist worldview is most likely correct, this does not actually make it any more or less likely. The reason I say this is because I refuse to assume that just because I percieve something one way, that it is then inherently MORE likely. That is just not true.
As I live my life every day, some unconscious and mundane symptoms do exist from my belief system, though. One such, is that whenever people are arguing endlessly, I realize that neither of them is actually sure they are right. They just adopted a position somewhere along the line, without knowing for sure, and go on arguing. It gives me a perspectve on history and specifically the history of human knowledge. Science and it's early forms seemed to be very fickle in changing their views of the world as soon as new information was discovered. It made me realize, "if every single theory previous to the ones we have now have been proven wrong, what makes me think that the ones we have now are any more right? Don't we have a long way to go in history after I die?" Generally, my beliefs give a whole new meaning to the phrase, "we may never know."
Indeed, the skepticism I mentioned has affected my everyday life in another way, namely that I am no longer a strict Christian because I now know that no one in my church knows what they know for sure, but they claim to, and that is lying. That bothered me so I left. The same thing, however, bothers me about some hard-core scientist types, who say "we KNOW" this and "we KNOW" that. They just don't. And when they just won't admit to that fact, it makes me rather disgusted with the belief they represent.
But, as I mentioned with the whole universal respect doctrine, at the end of the day I do concede to all these people that though they may represent their belief in a way I dislike, it still may be true. I can never know.
So... sorry to go on and on like that, but as you can see I really do believe what I am saying I'm not just playing Devil's advocate. Bottom line is: yes, for simplicity's sake I do assume I know some things, but I never presume, between me and myself, and anyone who will listen, to say that I really truly KNOW it. I just pretend to.