<human>: Do you ever find yourself in an ambiguous right-of-way situation and decide to be amicable by allowing the other person to go first, in traffic, for example, or at the supermarket?

Please explain to me, then, why some people, when you wave them through (offer to let them go first), respond by *waving you through*.

*No, you first. No, you! I said you can go, so go. No, please, you go first? GO GODDAMMITT!!!*

Is it some kind of competition? Why do they turn a courtesy into a competition that results in making an already ambiguous situation *more annoying*? Am I'm being unnecessarily helpful? Is offering them to go ahead some form of social welfare that's anathema to their personal philosophy? Or do they just not want me to stare at their huge asses? What is it?

Can you succinctly summarize the text in 1-3 sentences?
<bot>: Offer someone to go ahead, they reject the offer, instead telling you to go ahead, as if being courteous is a competition. Why?