Couple additional thoughts:

1) For some reason, I notice a good chunk of people who venture into FC to use the restroom are kids. Innocent little 4 or 5 year olds who probably just want to see what's behind the curtain. They aren't disruptive in any way; it breaks the "16 grumpy old men" atmosphere of the FC cabin.

2) 4 hours of sitting down anywhere can be a little dull on anyone's legs. Personally, and out of choice, I walk to the back of the plane. I'll wait in line, then use the restroom. It's an excuse to stretch my legs and stand up for 10 minutes. I generally can't stand waiting in lines.