You are in a very long line. A new line opens with cashier saying I can get whoever is next. Person in front of you is and goes. Then, person BEHIND you bee-lines it to that line even though you are supposed to be next. You are still standing in the original line. Who should be served? (I am not talking about being in stalls with buggies. I am talking about being at the post office or at the customer service desk.)

You

Customer BEHIND you

It should be you but really depends where I'm at in the very long line after person before me leaves. Do I go from 2nd in line to next in line or am I at the rear of the very long line. If that's the case it will create chaos with the next person in line trying to get to the newly opened line in which case I think the person in the rear should go. If you are in front and try to leave with buggy to get to next line you are creating a mess.