Leo Lichtman wrote:

[[...]] I ignore anyone who clearly doesn't want to interact,
e.g., high end bike, full costume, pedaling hard, [[...]]]

That's a strange assumption... How long does it take you to
distinguish between a "high end bike" and a "normal" bike?

The only time I don't greet someone is when going downhill at high
speed because that's too dangerous (and it doesn't make sense trying
to greet someone who is riding uphill while you go downhill at more
than, say, 60km/h).