I read a book about lucid dreaming a while back, and it said something like: the easiest way to tell you are in a dream is to look at something mechanical or complicated. The idea seemed to be: if you could get your dreaming mind to look at your hand and then turn it over to the other side, you didn't have the mental 'bandwidth' to imagine the opposite side correctly, and you'd realize you were dreaming. Equally, if…
Light switches and steering wheels never work properly in my dreams. I have to concentrate really hard to get things to follow the rules. Then I wake up.
Nope, nope, nope. Light switches never work properly in my own dreams either, but I find that testing the lights or just even noticing they aren't working is a guaranteed one-way trip to night terror land, even in adulthood. Not even realizing I'm dreaming is enough to stop it at that point.