Answer:
The French and Indian War saw calls for the colonists to unite for their common defense against the French and the Indians.
This was seen by Ben Franklin's JOIN or DIE poster.
In addition to this, the war debt Britain felt after the war led to the beginning of new taxes which the colonists didn't like ("No Taxation without Representation"). The colonists believed if they were to pay taxes, they should have a say (i.e. in Parliament) on where those taxes were going. As you probably know, this led to a whole slew events which escalated tensions (Townsend Act, Boston Tea Party, Intolerable Acts) and eventually the Continental Congress formed to raise an army.