They shouldn't get frustrated, but sometimes they do, and occasionally you'll get somebody who will push past you and then go and sit on the tail of the next guy. They only advance themselves one place in the queue, which gains them maybe a second or two, and it makes no sense in the overall scheme of things, but that's what they do. That's why I suggested trying to avoid the gap getting provocatively large, for want of a better expression.
Best wishes all, Dave - alias TripleS.