Through out the run of How I Met Your Mother the character of Barney Stinson has gone through a rollercoaster of transformations. From a diabolical ladies man, to a best friend, to a hopeless romantic, back to the ladies man, then to a husband, and eventually a father. It's not often shows like How I Met Your Mother take a main character on such a journey, but for Barney Stinson his character needed the journey to maintain his lovability. Without this change to Barney Stinson, How I Met Your Mother might not have lasted as long as it did.