So it was a kind of hidden pride. For you love to have the seat of honour in the synagogues and to be greeted with respect in the marketplaces. For you are like unmarked graves, and people walk over them without realizing it. Ample pride is displayed in our own day by religious people who refuse to listen to any point of view other than their own, because they're so certain they're right. And they appeal to Scripture or to Tradition to support their claims.
Pride is a terrible sin because it's a terrible block.
It forms a suit of armour around the wearer and therefore prevents anyone from getting near. It's so terrified of pain or hurt that it prevents vulnerability. And it prevents God from drawing near, for God can only work through openness and vulnerability. And pride distorts the true picture. It gives a false impression of the way things are, because with pride I'm only prepared to see through my eyes.