For Catholics we've got a lot of cool call and response stuff built into our liturgies that can easily translate to everyday life. So if someone in a truck shouts at me "Dominus Vobiscum", I know to say "Et cum spiritu tuo”.
I was wandering around down in the southern US a few day ago and someone in a truck yelled at me "Jesus Loves You". I thought that was wonderful and it really cheered me up. I waved and said "thanks".
Is there a cool thing that Protestants say (like "ping" - "pong" on IRC or that cool sign Harley guys do)? I know Bill Cosby thought it was cool that Protestants say "Amen", but I don't think that's an "Amen" moment. I want to say "Thanks for remembering me, Jesus loves you too!", I don't want to say "I know, ain't I cool".
Also, and this may be pertinent information to the question at hand, I really did look like a hobo at the time. I was walking from a Motel 6 to a Wafflehouse wearing 3 shirts, a jacket, a scraggly beard a stocking cap and carrying a mug and I'd just been camping for the weekend, the fact that I left my sleeping bag and over-stuffed backpack in the hotel room didn't seem to improve my appearance.