"hey... the back of the queue is back there!"
Exactamundo.
Sash and I were lining up to book or train trip in Venice and
some jerk jumped in front of us and asked to cut the queue, and he
made the mistake of having the unmitigated termrity to tell me,
"It's all right".
I said, "Is that a fact now?", turned to the fifty or so people
in the queue behind me and said, "Can I have you attention for a
minute? This fellow here just told me it's all right that he
jumps in ahead of all of us. What say you?". Some Yank
behind me immediately bellowed, "Hell no!".
By the time I turned back, our friend had retrested to a corner
to give me dirty looks. 