If you were a dream character, that means you would be MY dream character, because as far as I know, I have a mind. The person running the dream creates all the characters in it. If you have a mind of your own, then this is YOUR dream, and I am a creation of you. Everything I have written, and am writing, are not my own thoughts, but your thoughts being expressed through me. I could never prove to you that I am not a character in your dream, but you will never make me think that I am a character in your dream...
The thing that snapped me into realizing I was dreaming was, uh-- was my digital clock.
I couldn't really read it. It was like the circuitry was all screwed up or something.
Yeah, that's real common. And small printed material is pretty tough too.
Another good tip-off is trying to adjust light levels.
You can't really do that.
If you see a light switch nearby, turn it on and off and see if it works.
That's one of the few things you can't do in a lucid dream.