Why was George Washington's job as commander of the Continental Army difficult?
Lack of support.
George Washington was made commander of the Army by the Continental congress shortly after the Battles of Lexington and Concord. He immediately left for Cambridge Massachusetts where the American troops were encamped laying siege to Boston.
Upon his arrival he was absolutely disgusted and discouraged by what he saw in the troops assembled there. They were drinking and carousing, dirty and had no sign of military order. He knew had the British in Boston ever decided to attack these troops, the British would easily win.
In the first several years of the war Washington had to rely heavily on the militia supplied him by the various states. At the end of 1775 he found his troops preparing to head home as their enlistment only lasted until the end of the year. And what regular army troops he had were too few in number to defend anything.
These troops were also promised pay by a government that was virtually broke, and Washington knew that fact. This, a continuous lack of food, uniforms, weapons and trained troops were problematic throughout the war.