Or imagine you are queuing at a canteen with a lot of hungry people. Before you get there you think you want meatballs, but then whilst queueing you do some Googling and see that they use horsemeat in the meatballs so you decide to go for jacket potato instead. Would the person behind you in the queue that wanted jacket potato complain that you took his potato because he heard you talking earlier that you wanted meatballs?The thing about queue jumping:
Imagine you're at the store. And for each product there's a separate vendor with its own waiting queue. And at one moment you decide to go to another product, because your queue takes longer to advance. What do you do? Go right to the counter because you were there earlier than most of the people from the other queue? You'd be mauled there because you've jumped queues and expect to be treated preferentially. If you'd like the other product, you'd join the queue at the last existing position available to you.