My experience is exactly opposite.

Sure a big line is initially discouraging. But while in line, if I've chosen one of several lines, I fixate: is my chosen cashier a slow idiot? is a customer ahead of me fumbling for change? Should I jump? There's another line opening, should I get ready to run for it? I invariably end up at the front more directly annoyed and snippy at "my" cashier and the whole process. With a single line, I can see everything humming along, moving forward more often, if one transaction takes a while, so what, it's not a race, I relax more, I'll get there.

--which is why Delis‡ traditionally give you a numbered tag. It's a single line, but you can go about and not feel "constricted" to the queue (tail).

Don't forget, Frys also has a "semaphore" who cues people to the next register.

‡among many places like hospitals, information centers (DMVs), etc.

My favorite hardware store (Dunn Lumber in Seattle) does the same thing. It was difficult to get used to at first, but it's really nice to just take a number, wander around, and then not feel like you're holding anyone up if you don't order your lumber as fast as is humanly possible.