The most ironic moment of this story is when Sammy resigns. He is making a statement on behalf of the girls, being their hero. The irony is - they do not hear him. They are gone and out of the store before the moment of the resignation is even finalized.
...so I say "I quit" to Lengel quick enough for them to hear, hoping they'll stop and watch me, their unsuspected hero. They keep right on going, into the electric eye; the door flies open and they flicker across the lot to their car, ...leaving me with Lengel and a kink in his eyebrow.
However, the importance of this irony is that it drives Sammy forward, forcing him into a moment of maturity. He has an opportunity to take back his declaration, buy chooses not to. He wants to stand up for what he believes to have been injustice. This should be a moment of pride and celebration, but there lies the other irony - it isn't. Instead, this moment of adulty is marked by struggle, not achievement:
my stomach kind of fell as I felt how hard the world was going to be to me hereafter.
The symbols of this story revolve around the depiction of the customers. The girls are described as bees, the lead one being the queen, who have a certain power in the store as they buzz about it, making others nervous. The other customers are sheep, who flock together nervously, reacting but not responding to any situation. And certainly not thinking.