I've noticed that too, that expectations play a huge role in dreams. I use it in my lucid dreams sometimes. I can change the environment just by expecting it to be different, but my focus isn't always good enough for this to go as planned.

I've also found that talking to monsters tends to disarm and change them. I've never tried laughter, though! Sometimes, even when I know I'm dreaming, I'm too panicked to deal with the scary stuff and just fly away. But sticking around at least long enough for a good laugh might be doable.