Naomi - In a way, it's a shame you saw the Christmas Specials first, because the two series really do lead up to them.
For two series, Brent has tried, and failed, to be popular, and he has prostrated himself before deeply horrible people to gain their approval, especially the awful Chris Finch.
But finally, he finds someone who actually likes him, and he discovers that he can start to like himself, and that gives him the courage to kick back against the abuse he has taken, when it's aimed at someone he is starting to care about, a new experience for him.
A great payoff - hopefully you will now enjoy the two-series lead up to it.