What is one reason England did bad things to the colonies?

Honestly, the answer is pretty simple: because they could. 

England, an island nation, lacked many natural resources, and this was the motivating factor behind their various conquests around the world. Their relationship with the colonies, which was unequal to the extreme, gave them the "right" to demand taxes, goods, and labour of their subjects within those colonies. These demands were easy to make because the monarchy believed that these sacrifices were owed to them, as the rulers of the colonies. It is also far easier to demand hardships of people who are far away and whose threat is therefore, particularly in this era, greatly diminished. By draining the colonies of resources and heavily taxing them, England guaranteed that its own inhabitants would greatly prosper.