Big Kudos to you for not blowing your cool.
"Reacting" with reciprocal rudeness - as good as it feels in the moment - does not really help. It only reinforces the originally rude person's feelings of being justified in being rude in the first place. And whether you're first or second at being rude, being rude really only contributes to the rudeness in the world.
And while that kid is being "trained" by his mom, he's also watching how other people handle situations. So come here and vent, but good work not doing it right then!
