When you have a roommate/best-friend who's an Astrophysics major with a minor in philosophy, everyday conversations tend to go somewhat like this:
Me: "Hey, I saw Mike today, he was walking on college ave, I was in the car. I called out to him but he didn't hear me."
My Roommate : "Well yeah, your voice probably underwent Doppler degradation, compunded by wind and auditory interference. Now in a stellar vaccuous environment it would be possible to achieve 100% sound efficiency, but then again, to be able to live in space, we'd need various things - just today I was reading in Feynman's lectures that blah blah....."
Needless to say I've had my fair share of space-blabber. Based on some of that though, here's what I think. There's a whole lot of awesome stuff in space we know about, and about 99% more we don't know about. I'm sure everybody has though about where space ends, if it ends, when it ends, what's in it etc. The idea of space travel and life in space (both ours and others) is quite exciting - how feasible it is though I don't know.
There's one particular way I usually think about space. It's like this - everybody thinks that the planets are huge, nebulas are massive, galaxies are immense etc. However, break it down a bit - think of it like the human body. How do we know where we fit in. Is earth just another "molecule" in the grand scheme of things? Are people just part of that molecule? Are we protons, neutrons, quarks, strings? I think it's quite feasible that somewhere in the universe (I think I should define universe, because I've been in a great deal of arguments over this word. To me, the universe is everything. If something is, it is in the universe) there's a being who looks through his "microscope" and says - "Oh look, I've just isolated a strain of Galaxius Milkywaium." The planets, stars and everything else in the milkyway would just be part of this tiny thing.
On the other hand, it's quite possible that what we know today and what we percieve everything around us to be in terms of size and magnitude is correct, and there's nothing much bigger than a galaxy, or a cluster or other space objects.
I don't think too many (or even any) of these questions will ever be answered in our lifetime, but I still think they're worth thinking about - hey, atleast in some circles they make for good conversation