Because An Lingrong doesn't know how to interact with people.
Whether introverted, extroverted, sensitive, or carefree, these are just personality traits without any inherent superiority or inferiority.
An Lingrong is difficult to get along with not because she is sensitive and introverted, but because of the selfishness and coldness hidden beneath her sensitivity and introversion.
An Lingrong is very self-centered. She regards her own sincerity as particularly important and always feels that if she considers someone a friend, that person should consider her in everything.
The most typical example is when An Lingrong's father got into trouble, and she blamed Meizhuang for not doing enough for her.
However, her friendship with Meizhuang was only tentative because of Zhen Huan. When they first entered the palace, she only gave the hand warmer she made to Zhen Huan and not to Meizhuang. When Meizhuang faked her pregnancy and got into trouble, An Lingrong didn't worry about Meizhuang's survival but rather whether she would be implicated.
So, if she didn't consider Meizhuang a friend, why should Meizhuang be obligated to do her best for her? Besides, Meizhuang wrote a letter to her family, which was a favor even if it was a minor one—better than nothing.
Zhen Huan, on the other hand, genuinely cared for An Lingrong, earning the recognition of both An Lingrong and her maid.
"Whoever treats me well, I remember it."
Did An Lingrong express her gratitude towards Zhen Huan? No!
She only condescendingly evaluated Zhen Huan, saying, "You have been sincere to me, good, you deserve my sincerity."
True friendship is revealed in times of adversity. An Lingrong always felt she was sincere towards Zhen Huan, but her kindness towards Zhen Huan was just adding icing on the cake when Zhen Huan was favored. When Zhen Huan fell from favor, An Lingrong avoided her.
Throughout the series, the only two things An Lingrong did for Zhen Huan's sake were killing Yu Ying'er in the Cold Palace and sending Zhen Huan the brocade.
Both of these acts occurred when Zhen Huan was in favor.
However, An Lingrong was responsible for Zhen Huan's first fall from favor. She harmed Zhen Huan's child and prevented the big orange cat from seeing Zhen Huan.
As for Zhen Huan, she defended An Lingrong against Xia Dongchun and saved her father. Wasn't that helping in a time of need?
But when An Lingrong used musk against Zhen Huan, did she ever feel guilty?
In essence, An Lingrong is selfish and cold. Being friends with her requires you to abandon your legitimate needs and prioritize her in everything. Only when you do this will you receive her acknowledgment, "I know who treats me well."
The key is, who cares about your acknowledgment? If someone treats you well, you should reciprocate.
