Time's Arrow

I've written a bit about this before, but I'm still baffled by time. And I don't mean how you can lose an entire evening watching COPS, that part of time I understand perfectly. I mean what is time, why do we experience it, and why - from our perspective at least - does time only flow in one direction.
   Since we're embedded in time, I suppose you could think of it as being a fish in a stream. If you asked the fish to explain the current, why it always flowed downhill, and why they were in the stream in the first place the fish would probably have no explanation. They would probably not have given it a second thought prior to you bringing it up, since they wouldn't know any other way. Being in the center of a phenomenon doesn't make for the best observation point to explain that phenomenon.
   But that prompts the next question. If you and I and everyone else on this planet, solar system, galaxy and universe are stuck in the one-way stream of time, is there some other vantage point? Can someone or something be outside of time? And if there were something or someone outside of time, how would we be able to tell that, seeing as how we're stuck in the center of it?
   I know there are various philosophical and epistemological discussions about the arrow of time, about the Second Law of Thermodynamics and increasing entropy, blah blah blah blah blah. This is all talking around the subject and ignoring the 800 pound gorilla of a problem: we don't know what time is.*
   We experience time - or, perhaps more accurately, the effects of time - but we can't explain it like we can a smell or a sensation or a sight. We can see the minute hand marching forward on the clock but we can't explain what that is or why we can't make the minute hand go backwards.
   And then let's consider the concept of time for animals. We're kind of bound to the clock and the hours of the day. Dogs can't read a clock (I suppose), so what is their concept of time? They're stuck in the middle of it like we are, but is their experience of it different? What about tortoises? Or giraffes? Or zooplankton? Or mosquitoes?
   It seems to me that time is experiential, in that it moves subjectively faster or slower depending on what you're doing. Time flies when you're having fun, after all. But why should that be? If we're stuck in the one-way arrow of time, why does our experience of it vary? What does that mean? Could we have a sufficiently sublime experience that stops time altogether, at least for a little while?
   This is the kind of stuff that keeps me up at night. Really.

* not what time it is, we already know what time it is. It's time to get ill.