That's why it's sometimes good to know a second language, to %$#@& the heck out of them so you feel better, but they can't feel too offended cause they have no idea what you said, but sense "the devil" must've possesed you for a while!
Well, Lindsay, I can relate to being "commentless", cause there is the need to say something without posing a challenge, or to be more intellegent in the return reply. I still have to learn to reply to such situations, but from my sister, it seems the best way to reply is to indicate how you feel about their such behavior.
To say to the lady, something like "I don't have anything contagious, and find your thoughtless comment is unnecessary."
Though, this particular time, as I had been going through the ticket entrance at the train station, this young man (punk?) had rudely cut in front of me, and said nothing to excuse himself. I also wanted to say something, but like you, was somewhat seemingly more speechless from his act, that by the time I could say anything he was too far away for me to do anything. I just had to put in my mind to not allow something like that happen to me, again, and to speak up, immediately, if I don't want to feel regrets from not doing so before.
Considering how there are so many rude people in society, I'm sure you'll get your practice, just like me.
As for rude drivers, I sometimes wonder if they got their skills from too many driving video games!!
I sometimes wish I had an extra clunker, just to play chicken with some of them!! Like, an old Chrystler!! I'd take up the WHOLE road, against their little "motorcycle engine" cars!!
I just try not to become one of them, when I'm driving. Unfortunately in Japan, it's difficult, cause I have to watch in front, AND behind me for such rude (and dangerous) drivers!! (But, those adventures are a different story!!)
"Don't Worry, be Happy!"
O-Genki ni!