Question

It is believed that Sir Gawain and the Green Knight was written in the late 1300s, as the age of chivalry began to wane. Though the legend has it that Gawain was one of the Arthur’s finest and most loyal knights, the Gawain poet depicts him as flawed. Why might Gawain poet have portrayed Gawain this way?

Answer 1

Because he maybe written into the book of rivalries that happened at that time

Answer 2

Think of what could have happened, like friends becoming enemies over something, or breaking down of wars causing "illusions" to your own comrads being enemies and so forth and answer from there.