Well, to sum up your question of "Why do people hate America so much?" I'm going to try to explain as quickly as possible, using global politics as much as possible.
c1915 (WWI) - Woodrow Wilson is president, progressive, with many "idealistic" programs such as the League of Nations. The world (especially the allied world at the time) views America as an important global partner, and America views the world as the same. (This explains why America would NOT interfere with English blockade of German ships during WWI, even though it went against our policy of neutrality.)
c1945 (WWII) - FDR/Truman is president, the (allied) world still views America as an important global partner, but America is beginning to see herself as the leader of the Western world.
c1970 (Vietnam War) - Backed by Lyndon B. Johnson's increase in troops in Vietnam (to 500,000 from JFK's 50,000), America now takes it upon herself to create the change she wishes to see in the world. As part of the Cold War, it was America's first venture into imperialism.
c1980s (Arms/Space Race) - Ronald Reagan created a 1 trillion dollar deficit en route to dismantling the USSR, and essentially effectively defeating Communism. It solidified America's position as the number 1 superpower in the world - no ifs ands or buts about it now. The world, perhaps, begins to get jealous.
c1991 (Desert Storm) - America now begins to assert herself as the world's number 1 superpower by no longer using domestic means to outdo other nations (such as the arms race), but is now venturing into other countries to maintain superpower status.
cGeorge Bush - Following his fathers mishandling (that is a debatable issue) of Desert Storm, Bush Jr leads what is now considered by a thoroughly offended council of nations a "warmongering"-type of nation. Europe is angry about the lack of WMD, also that Bush proceeded without UN support. The USA currently has about 50,000 soldiers that REMAIN on the Korean border, 50 someodd years after the Korean War is over. Any foriegn conflict since 1990 that you can think of, America has had a say in it somehow. Perhaps our constant eye, our goverments wish to instill democracy in EVERY nation, is what leads to this dislike of the USA.