Final answer:
Americans were upset with British trade laws because these laws enforced strict trade limits, hindering their ability to trade freely and access goods from other countries. The enforcement measures and direct taxes after the French and Indian War heightened tensions, leading to widespread colonial dissatisfaction.
Step-by-step explanation:
Americans grew upset with the British over trade laws primarily because the British began to strictly enforce the laws with such measures as writs of assistance. These laws contradicted the established practice whereby Americans were accustomed to trading with whomever they wanted. Additionally, British mercantile laws severely limited American access to goods from other countries.
The Navigation Acts and other trade restrictions were devised to prioritize British economic interests, dictating that certain colonial products could only be sold to England or its possessions. These restrictions, along with measures like the Woolens Act and the Molasses Act, constrained colonial industry and trade. Smuggling became a common practice as merchants sought to loophole these limitations.
After the French and Indian War, Britain sought to raise revenue to pay its debts and maintain its army in North America. This led to harsher enforcement, including requiring trials without jury for suspected smugglers, and the imposition of direct taxes, exacerbating colonial discontent.