It’s so easy to forget to do this, but it makes the world of difference for road-user relations. If an oncoming vehicle has let you and/or your group have space to make a turn or have access to a narrow stretch of road first, acknowledge them with a raised hand of thanks. Making this sign obvious – for example with an additional smile or a raised thumb – can help ‘humanise’ you on the road, and conveys genuine appreciation for the actions of the other road user.
It’s also a fine road cycling tradition, especially in the UK, that road cyclists acknowledge each other as they pass by. A nod of the head and smile, or a hand raised off the ‘bar, will do the trick for oncoming riders, or just say “hello” if passing a cyclist on the same side of the road. Be nice out there!