Which elements of the daily life of the Third Reich are generally thought of having been created by national socialists but had already existed during the Weimar republic?
I've had a look at a couple of Fritz Lang's films from the end of the Weimar period. Some of the visual feeling in the movies, including clothing, gadgets and office furniture, looks stereotypically Nazi to me but was actually something you could already see a few years before Nazis came to power.
For instance, there were long leather coats that I had thought hadn't generally been used in Germany prior to the Nazi period. I suppose that's merely a popular culture cliché.
I'll take a bite at this one.
One of the common images of the Third Reich is a paramilitarized youth movement like the Hitler Youth. For example, the cheesy film Swing Kids portrays the Hitler Youth slowly working its way into the minds of German jazz fans. However, many different political factions within Weimar had their own youth wing with their attendant uniforms and drill. The Stahlhelm, the paramilitary of the conservative DNVP, has the Jungstahlheim. The official journal of the Jungstahlhelm- Die Standarte- became so radical that the official leadership of the Stahlhelm disassociated themselves from its publication. The Kommunistischer Jugendverband Deutschlands was the youth branch for the German Communist Party. The infamous Nazi novel and film Hitlerjunge Quex would set up the members of the Communist youth organization as antagonists to the film's titular protagonist. In the film, the Communist youth are "bad" kids who drink, smoke, and mixed-gender (one commie youth gives a German girl a playful spanking on a train ride). Even the democratically-orientated SPD had their own branch of paramilitary youth and incorporated such strictures in the 1930s. According to the historian Frank Bajor, despite their different ideologies ranging from democratic socialism to Nazism and Communism, in appearance the paramilitary youth "were almost indistinguishable in their outer appearance."
Sources
Brown, Timothy Scott. Weimar Radicals: Nazis and Communists between Authenticity and Performance. New York: Berghahn Books, 2009.
Hellfeld, Matthias von, and Wilfried Breyvogel, editors. Piraten, Swings, und Junge Garde: Jugendwiderstand im Nationalsozialismus. Bonn: J.H.W. Dietz, 1991.