I have tried, generally successfully, to break myself of any bad habits involving obscene gestures and/or verbiage. A friendly wave and/or a smile is a thoroughly disarming response to horn honks, "get off the road," etc. I recall when air horns first came out in the early 1970s, and we did quite a business in them at Bikecology for awhile, but I haven't used one in years. I am not shy about raising my voice to enhance my safety, but I try to be careful about the content of my message when I do.
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"Far and away the best prize that life offers is the chance to work hard at work worth doing." --Theodore Roosevelt
Capo: 1959 Modell Campagnolo, S/N 40324; 1960 Sieger (2), S/N 42624, 42597
Carlton: 1962 Franco Suisse, S/N K7911
Peugeot: 1970 UO-8, S/N 0010468
Bianchi: 1982 Campione d'Italia, S/N 1.M9914
Schwinn: 1988 Project KOM-10, S/N F804069