‘Lady Catherine de Bourgh.’ It vexed her to see him expose himself to such a man.” This shows how even though it was considered weird to introduce yourself to someone you don’t know only on the notion that you know their aunt, Collins does it anyway. In a way it can even seem disrespectful because Collins only wants to be aquatinted with him because of his money and power. 

“She was teased by Mr. Collins, who continued most persever- ingly by her side, and though he could not prevail on her to dance with him again, put it out of her power to dance with others. He assured her, that as to dancing, he was per-fectly indifferent to it; that his chief object was by delicate attentions to recommend himself to her and that he should therefore make a point of remaining close to her the whole evening.  There was no arguing upon such a project.”  She is not interested in Collins and is therefore annoyed and embarrassed by his following her around. She is now realizing that Collins is likely to try to continue their relationship by proposing.