GLaDOS is great. Witty, passive-aggressive, and completely insane.

As for missing dream signs, all I can say is that on the pathway to lucid dreaming, be prepared to forgive yourself often. I've certainly missed out on loads of incredibly obvious dreamsigns. All you can do is laugh at yourself. (I posted a really egregious one in Daily Snippets if you'd prefer to laugh at me instead.)

Considering that in non-lucid dreams we function (as far as today's science understands) with important parts of our brains virtually inactive, it's pretty understandable.