Why does the World give American troops a hard time about there Professionalism!!?

Just something iv never really understood, Having served in the British Army alongside many Us Branches of their military especially the 2nd Battalion, 19th Field Artillery in Combat Theatre they seemed as Professional as any other western military, In some cases even more professional than most European Armies.. Yea they shout and are loud when a bomb hits the target but i dont know of any army that doesnt act any different.. And before people talk about friendly fire in the air just bare in mind that they provide about 70-80% of the air support in afghanistan , and per ratio of accidents to the amount of Personel and Equipment they got their statistics are as low as everyone else.....