Motorists across the world witness a familiar pattern every spring and summer: two complete strangers momentarily share a visible sign of camaraderie, then roar away from one another in the blink of an eye. The commonality between the two strangers is obvious to even the most aloof automobile driver. 
 
The history of our wave isn’t well documented, but perhaps it need not be. Taking a motorcycle ride on a nice day is the type of thing that generates copious amounts of joy, and most humans treat a surplus of joy as a windfall and give some of it away. The wave is self-explanatory, but some riders could benefit from clarification on a few points. 

Wave when it’s safe
There are definitely times you might not be able to wave. If you’re setting up for a corner or grabbing a handful of clutch for an impending gear change, veteran riders will know why your hands remain on the grips. If you’re a lone rider passing a large group, it’s inconvenient in that situation as well, and in a bike-heavy area (like a rally) waving is also not expected. 
 
Don’t stress it! It’s supposed to be a fun inside thing, not a social tax. We understand, and you should too, that if someone seems to ignore your wave, it’s not a slight against you. If you’re militant about appearing nice in all scenarios, try just lifting a finger up off the grips; that’s often a bit easier to manage!

In fact, not waving might not be safe 
Anyone who rides long enough will miss a few waves from not paying attention. Enjoying your surroundings is great, but if you’re late on a wave or miss one entirely, it sometimes serves as a reminder to start scanning the horizon a bit more carefully. 

What has two wheels, handlebars and a rider on top pinning the throttle?
Well, it could be someone sliding an XG750RTM around a flat track, but it might also be a scooter. Motorcyclists seem to be sharply divided on waving, or returning waves, to scooterists. Mama raised me to be polite, so I wave to anyone – there’s no punishment for being too nice. My personal philosophy also extends to people on, or in, trikes, combine harvesters, brightly coloured vehicles, and any youngster not travelling by way of shoe leather. 
 
That might not be a wave 
Harley-Davidson^® motorcycles don’t die; they just get rebuilt. There are a lot of us riding old and heavily modified motorcycles that necessitate hand-signalling. It’s also very common in large groups of riders, even ones on modern machinery. Make extra sure that an oncoming rider is waving, not indicating a turn. You’ve got to interpret hand movements correctly for safety’s sake. 

It’s not just us
Corvettes and Wranglers are vehicles that also have a pretty hardcore waving contingent among owners, and classic Mazda MX-5 owners often use their flip-up headlights as a form of wave. However, the wave motorcyclists share is uniquely model agnostic. Race replica riders, dirt enthusiasts and the kid down the street on a moped would all appreciate a five-fingered acknowledgement. 
 
Wave to the cars, too
You may receive a wave from a stranger in an old truck – that’s probably one of us who has simply forgotten they’re not on a bike! You’ll probably do it at some point eventually, and this is the usual explanation for mysterious waves from unknown individuals in a vehicle with too many tyres. 
 
In summation, you only need to remember the cardinal rule of waving: it doesn’t matter, because there are no rules. There’s really only one wrong way to participate in this exercise – ‘crashing waves’ are best left to boats, not motorcycles.