Venn diagrams are in, so I decided to try my hand at them. (Click to enlarge)
As you can see, of the time that I spend on the Metro, 0% of that is shared with the time that I am happy. In statistics, they call it mutually exclusive: events that cannot occur at the same time. By virtue of being on the worst public transportation system in the world you cannot be happy. And you can be happy as long as you're not on the red line, or any line or bus that makes up DC Metro.