When you dream you're solving physics problems and relate your dream to your engineer spouse like this:
You: "So in my dream, there was a rotating disk with an inner circumference and the outer edge. I had to find the difference in force and speed between the two points."
Engineer: "You mean the torque?"
You: "Yes, but I had to try to do the math in my head, since I was dreaming and there was no calculator I could use. So I'm trying to do 'pi r squared' in my head for this disk. Then I had to figure out the accelaration on the outer edge. I didn't know how to do that part."
Engineer "Torque = Force x Distance."
You: "Well, I didn't know that part. All I could remember was that Force = Mass x Acceleration."
Engineer: "Yeah. Torque = MAD."
Then he looks at you, his Arts major spouse and says "You've been married to an Engineer too long if you're starting to dream physics!"