The relationship between the King and Parliament broke down for a number of reasons:
limiting Parliament’s power
Religion - a return to Catholicism
At the time the Catholic faith was feared by the crown. Remember, Charles I's father James I, had been the target of the Gunpowder Plot of 1605.
Charles I married Henrietta Maria, a Roman Catholic from France. Parliament feared this was a sign that he sympathised with Catholics and that she would influence his religious policy.
The Archbishop of Canterbury, William Laud, introduced Arminian reforms into the Church of England. Arminian practices are closer to Catholicism than other forms of Protestantism and include using candles and bowing at the name of Jesus.
Many MPs were Puritans. They thought Charles wanted to make England Catholic again.
Charles believed in the Divine Right of Kings. This is the idea that God had chosen him to be king and that Parliament had a less important role in government. Protestants believed that, like in their relationship in prayer with God, there was a closer dialogue between the ruler and the ruled.
Foreign policy - failed and costly wars
A attack on Spain in 1625 failed.
An attack on France in 1627 failed. In 1627, Charles sent a military force to France to support Hugenots (French Protestants). It failed and was also very expensive, losing Charles even more support at home.
Limiting the power of Parliament - abolition of Parliament and abuse of laws
People came to believe that Charles was undermining their liberties or rights:
Charles used a private 'Court of the Star Chamber' to try and punish his opponents.
When Parliament complained in 1629, he dismissed them. Until 1640, Charles ruled without a Parliament, a period known as the 'Eleven Years Tyranny'.
Charles needed to raise money without Parliament so he used old laws such as Ship Money, which was a tax collected from coastal towns in the Middle Ages to pay for the navy. In 1635 Charles made inland counties pay it too. Charles also found a forgotten law that said that anyone earning more than £40 a year had to be a knight. In 1630 he started fining people who had not obeyed.
The MP John Hampden refused to pay in 1637 and narrowly lost the subsequent court case, but his stand gathered support for the dissenters.