Why does the Old Testament God seem different than the New Testament God?

There are lots of people, both young and old, men and women, educated and uneducated, experienced and inexperienced in life; people from all walks of life, who believe that God presents himself differently in the Old Testament than he has in the New Testament. Worse yet, there are those who would see the OT and NT as presenting two entirely different gods. Not true. Let's dive in and answer this question.