In short: much less enthusiastic.

If I may, here is an extended quote from William Shirer's "Berlin Diary". I've seen this quoted in many popular histories of the Third Reich (Richard Evans comes to mind).

"I was standing in the Wilhelmplatz about noon when the loud-speakers suddenly announced that England had >declared herself at war with Germany. Some 250 people were standing there in the sun. They listened attentively >to the announcement. When it was finished, there was not a murmur. They just stood there as they were before. Stunned. The people cannot realize yet that Hitler has led them into a world war. No issue has been >created for them yet, though as this day wears on, it is plain that " Albion's perfidy " will become the issue as it >did in 1914. In Mein Kampf Hitler says the greatest mistake the Kaiser made was to fight England, and Germany must never repeat that mistake.

It has been a lovely September day, the sun shining, the air balmy, the sort of day the Berliner loves to spend in >the woods or on the lakes near by. I walked in the streets. On the faces of the people astonishment, depression. >Until today they have been going about their business pretty much as usual. There were food cards and soap cards and you couldn't get any gasoline and at night it was difficult stumbling around in the blackout. >But the war in the east has seemed a bit far away to them — two moonlight nights and not a single Polish plane >over Berlin to bring destruction — and the papers saying that German troops have been advancing all along the line, that the Polish air force has been destroyed. Last night I heard Germans talking of the " Polish >thing " lasting but a few weeks, or months at the most. Few believed that Britain and France would move. >Ribbentrop was sure they wouldn't and had told the Fuehrer, who believed him. The British and French had been accommodating before. Another Munich, why not ? Yesterday, when it seemed that London and Paris >were hesitating, everyone, including those in the Wilhelmstrasse, was optimistic. Why not? In 1914, I believe, the excitement in Berlin on the first day of the World War was tremendous. Today, no >excitement, no hurrahs, no cheering, no throwing of flowers, no war fever, no war hysteria. There is not even any >hate for the French and British — despite Hitler's various proclamations to the people, the party, the East Army, the West Army, accusing the " English warmongers and capitalistic Jews " of starting this war. When I >passed the French and British embassies this afternoon, the sidewalk in front of each of them was deserted. A >lone Schupo paced up and down before each."

Something that Richard Evans has mentioned in his histories is that the "August 1914 spirit" was very much a feeling that the Nazi regime was hoping to recreate during its rule: a nation enthusiastically united in patriotism behind a mobilized military. But there were significant reasons why September 1939 was not August 1914.

One of them was, of course, that the First World War was already a very dark, looming recent memory in 1939, in a way that no war was for Germans in 1914 (the Franco-Prussian War was 50 years in the past). So the average German population was already more primed to fear a protracted conflict in 1939. It's worth remembering that Germany suffered more military casualties than any other country in World War I, and also suffered something like a million excess civilian deaths during that war because of malnutrition caused by the war's blockade, and attendant public heath issues.

The outbreak of war in 1914 was also the result of a relatively quick international crisis over the summer, while the outbreak of war in 1939 was a crisis years in the making. Many across Europe had expected general war to come in 1938 over Czechoslovakia, and this was seen as averted at the last minute by the Munich Agreement (as Shirer alludes to). Mobilization for war was already underway in Germany, Britain and France (as evidenced by the rationing Shirer mentions), so for civilians there was already a pinch being felt before the conflict came, unlike in 1914.

Perceptions of war had also radically changed. This probably heralds back to the old adage about always fighting the previous war. 1914 was expected to be like 1870, only on a far larger scale. There was a sense, therefore that a war would be relatively quick and glorious. In contrast, in 1938-1939 many people in Britain, France and Germany expected a new war to be a repeat of World War I, but on a more horrific scale: mass aerial bombings of cities with poison gas were expected within minutes of war being declared (this is something Richard Overy discusses in his books "The Morbid Age" and "The Bombing War"). Strategically and technologically, this was beyond realistic capabilities, and did not happen, but the general fear of such dire events was real in 1939.

The Germany of August 1914 and the Germany of September 1939 were also very different places. For all of its illiberal features, the Second Reich had elections and multiple parties in the Reichstag, most of whom enthusiastically endorsed war in 1914. In 1939, there was no such legitimate political spectrum.