One of the methods Churchill used to exert a measure of control, which also helped him to come to grips with issues, was interrogation. Military analyst Eliot Cohen writes that Churchill did not just ask a question and then forget it; he followed up with "a relentless querying of their assumptions and arguments, not just once but in successive iterations of a debate." While at times this drove his generals and aides crazy, it did keep Churchill informed and his direct reports on their toes. Churchill, unlike other wartime leaders, was both a former military officer and a historian. So while his questions may have irritated his generals and aides, and while at times he did go too far, Churchill's breadth of knowledge lent him a greater degree of credibility in military matters.
One story among many illustrates Churchill's insight as well as his willingness to ferret out answers. Upon learning that regimental patches (a form of military insignia) were no longer being issued to British troops, Churchill investigated. The Army Office said that it was cooperating with the Board of Trade, which had forbidden the patches as an unnecessary use of cloth. In reality, the Board of Trade had no problem with the patches; the Army was making excuses for its "wildly unpopular decision." The real issue, as Churchill understood, was not a patch of cloth; it was esprit de corps. British Tommies identified with their regiments; to deprive them of this distinction would adversely affect morale. The regimental patches returned.
Unlike lesser leaders, Churchill expected his generals to disagree with him. He did not want yes men; he wanted commanders who could think and plan for themselves. And this is why he had such fractious relationships with his chiefs of staff. By repeatedly questioning their decision making, Churchill assured himself, and by extension the British people, that their military strategies were sound. Mistakes were made, of course, but Cohen believes that Churchill's hands-on approach, chiefly by virtue of his communications, was the proper course.
Churchill was a pragmatist. He was elected to Parliament as a member of the Liberal party, and he was a minister in David Lloyd George's cabinets before and during the First World War. When the fortunes of the Liberals declined, he declared for the Conservatives, his father's party, and in the late 1920s became chancellor of the exchequer, again something his father had been. His party switch was opportunistic, of course, but it was born of his need to be in the thick of the action, to be of service, to be doing something of value and merit. As a result of his opportunism, he was widely disliked throughout his career by those of his own class as well as by party loyalists. As his biographers point out, it was his service as prime minister that endeared him to the people. Prior to that, all too often he had been regarded more as a busybody, an opportunist, and a self-promoter.
Contrary to his image as a tough leader, Churchill was repeatedly kind to his adversaries once he had defeated them. He kept his predecessor, Neville Chamberlain, whom he had criticized for his appeasement strategy in dealing with Hitler, in his War Cabinet. In part this was due to the fact that most Conservatives favored Chamberlain over Churchill; nonetheless, Churchill was generous to his political enemies after the battle was won—something his adversaries were not throughout his long career in politics. (When Chamberlain died in November 1940, Churchill gave a eulogy for him in the House of Commons.) 
Churchill put his own perspective on his wartime leadership when he said to the House of Commons in 1954, "It was a nation and race dwelling all around the globe that had the lion heart. I had the luck to be called upon to give the roar." Never have the forces of freedom been blessed with such a roar!