Interesting dreamsign.... just goes to show, everyone is different.
One reality check I have heard of is that people in your dreams have a different reaction when you ask them whether you're dreaming.
In waking world, they tell you that you're insane. In dream they tell you 'of course not... I promise.. you're not... etc'
Either that or they admit it

Problem with that reality check is that I would hate to do that every 30 minutes in the waking world. Someone will eventually lock me away for good.