Here's a quirky article from November, 2013, about a Trader Joe's in Manhattan, and specifically an employee whose job is to help people find the end of the line (which otherwise melts into the crowd of shoppers).
I'm glad my TJ's is not anything like the one described in the article. If that were the typical experience of shopping there, I wouldn't go half as often as I do. My store is a much smaller one. I think they have six cash registers, maybe seven. I have never had more than three people ahead of me in a checkout line, and I'd guess that the average number of people ahead of me in line has been one.
Hat tip to the "Things I Love at Trader Joe's" blog for their post about the story.