This is my opinion:
From the viewpoint of a non-American, I would say that yes, the US does seem to be the world's bully. And a selfish one at that. Why does the US stick it's nose in some world affairs while ignoring the rest?
Kuwait 1991 = oil: get involved
Iraq 2003=oil: get involved
Cambodia 1975(ish)= proven no-win situation in Vietnam: don't get involved
numerous civil wars in Africa (perpetual)= nothing to gain: don't get involved
There are more examples, but you get the point. Now as far as history goes, the US has a tendancy to seek glory where it is not deserved. Look at WW2 and the liberation of Rome. The Canadian army did the work, then were ordered by the US to stand down while US troops rolled in and took the glory. But yes, the US was necessary to defeat Germany in 1945. In WW1 the Canadian army was a major factor in defeat of the Germans at Somme, Ypres, Vimy Ridge, Pashendale etc. but the US history portrays the American armies entrance to WW1 in 1917 as the factor in the defeat of Germany. The statistics prove this to be wrong.
I don't disagree that the US is a necessary evil as LB elludes to. But don't be so surprised that the rest of the world doesn't like you. Even your closest friend to the north tolerates you, maybe even needs you, but we don't really like you.
Stan