Obviously there were many reactions to his program. As long as he seemed to be supporting "law and order" and was fixing the economy of Germany the majority of the population there supported him. There was opposition, and not just from the Communists. There were resistance groups, including university student groups, whose leaders were of course arrested, imprisoned, tortured and murdered. As the war dragged on and hope of succes was lost (and as some learned more about the concentration camps) there was more resistance among the military and the old aristocracy. There were at least 17 attempts at assasination, all of which ended in disaster for the conspirators.
As Hitler's regime gained more power through the 1930s the propaganda mitigated against resistance. Everything in German society was propagandized, including the education system and textbooks. Mathematical problems often involved word questions using examples of war. Instead of "two trains going x m.p.h. left at the same time etc." problems might involve how fast a Stuka dive bomber could reach Belgium, etc. All aspects of society were involved, and so resistance was put down by reeducation as well as by the carrot and stick methods of economic improvement and fear of reprisals.
In other countries reactions were also varied. Some people realized there could be no compromise with the Nazis and their philosophy (Winston Churchill and President Roosevelt would be good examples), while others believed diplomacy and appeasement would keep Hitler within bounds (such as British P.M. Neville Chambelain). But there were many people in Europe, including average citizens as well as political and military personalities, who agreed with Hitler's views. His supporters in many countries eased the path of invasion, as Quisling in Norway, and Waffen SS military units were raised in countries all across the continent. Most of the SS troops still fighting the Soviet forces in Berlin at the end of the war were French.
Even Americans were involved, and members of the British aristocracy. One of the Bush family banks was closed by the US government during the war for collaboration, and Standard Oil was accused by the US Army of selling fuel oil to Nazi submarines outside the three mile limit. For the full story of German economic penetration and how Hitler's plans were really thwarted, I suggest A Man Called INTREPID, by William Stevenson.
After the death of Hitler's parents his political views began to develop.Eventually he ended up in a homeless shelter and was introduced to a man named Liebenfels, whose political concepts were extreme. Leibenfels believed in the superiority of the Aryan race, and the inferiority of other races, especially the Jews.
At the founder's insistence, Hitler joined the German Worker's Party. He quickly became the party's spokesperson and his speeches were attended by the thousands. Eventually he was discharged from the Army in 1920, by 1921 he learned of an attempt to dilute his influence and rushed back to Munich to confront his adversaries. He threatened to leave the party, and since he was responsible for the large share of the funding of the party, he was appointed absolute leader, or Fuhrer, on July 29, 1921.
So to partially answer the question; yes many disagreed with Hitler's ideals and anyone who was not a Nazi was taken to a concentration camp, which quickly dispelled any dissent. A bomb was placed in his East Prussia headquarters, but did not kill him. Germany's support of Hitler was due to the fact of publicly condemning him and being killed.