Call it the Farmer Wave, the Rancher Wave, or the [Blank] wave, you had better learn it hereabouts too. In Iowa, it has an official week, which is just now ending.
And then there is the Jeep Wave. Instead of saying "I trust you," it is saying, "You're more hardcore than I am. And I trust you."
Protocol dictates that (usually) the owner of the newer Jeep wave first, so when driving my 1973 CJ-5 I can just cruise regally along, awaiting my due acknowlegement.
It gets at least 50 points on this scale.
But I keep an eye out for that guy down in town who has the CJ-3B.