Why walk all the way to the back of the queue and go through the maze of zig zag pathways when one could just enter from the front (given theres only 1 - 3 people at the front of the queue). Simply present a smile, say "Excuse Me" and "Thank You" and you would have saved yourself 1 min of time and effort of walking.
One might say walking is good: its exercising; what if you start from the back of the queue and someone used the above strategy and came in front of you; How would you feel?
Most would just simply be silent.