Our country was founded in common law according to Thomas Jefferson, but as early as 1799 he noted in a letter to Edmond Randolph that the law had already slipped into equity or chancery, which he believed to be scourge of freedom. Equity courts come from the ecclesiastical side of justice. The king ruled the courts of law, and the church controlled equity. Equity has many noble honors such as being the theater for inquisitions and star chambers. Common law grew from the desire of the common man to have a forum that would net swift, inexpensive and final results for the common folks.
Common law can be harsh, because the rule of law is inflexible.
Just as you do not plant corn in November because of Nature's Law, you do not violate common law and expect a harvest. To protect against its inflexibility, the jury was given a great power to ignore any law that was unjust or was being unfairly applied. In common law, an informed jury was assembled, a jury that knew all parties, hence their reputations for truth and veracity. The jury was given all of the facts without the constraint of ridiculous procedural traps laid in equity, and the jury made a decision on the spot. From that ruling, there was no appeal except in extraordinary cases.