Mother Teresa of Calcutta is idolized by Roman Catholics and others worldwide, mostly conservatives. There have been criticisms that she made a big show of caring and gave inadequate care. This makes her a horrible person (or horribly misguided) unworthy of any credit.
This returns us to the medieval corruption of the church, which sold indulgences to the rich while preaching hellfire and continence to the poor. MT was not a friend of the poor. She was a friend of poverty. She said that suffering was a gift from God. She spent her life opposing the only known cure for poverty, which is the empowerment of women and the emancipation of them from a livestock version of compulsory reproduction. And she was a friend to the worst of the rich, taking misappropriated money from the atrocious Duvalier family in Haiti (whose rule she praised in return) (...) Where did that money, and all the other donations, go? The primitive hospice in Calcutta was as run down when she died as it always had been—she preferred California clinics when she got sick herself—and her order always refused to publish any audit. But we have her own claim that she opened 500 convents in more than a hundred countries, all bearing the name of her own order. Excuse me, but this is modesty and humility? 
Mother Teresa provided inadequate painkillers, her staff washed injection needles instead of sterilizing then, she wouldn't even send a 15 year old boy to hospital though his life could probably have been saved. She allowed overuse of restraints at her flagship orphanage, which was compared to a Romanian orphanage. 
Worse, she actually had relationships with some wealthy and corrupt individuals such as former Haitian dictator Jean-Claude Duvalier and his wife Michèle Duvalier and she even accepted the misappropriated money from them, also from enigmatic quasi-religious and New Age Movement figure John-Roger, and former financial executive Charles Keating who was convicted of fraud.
It is suspected that she ditched her religion sometime before she died. She was said to have said; "I call, I cling, I want ... and there is no One to answer ... no One on Whom I can cling ... no, No One. Alone ... Where is my Faith ... even deep down right in there is nothing, but emptiness & darkness ... My God ... how painful is this unknown pain ... I have no Faith ... I dare not utter the words & thoughts that crowd in my heart ... & make me suffer untold agony.
So many unanswered questions live within me afraid to uncover them ... because of the blasphemy ... If there be God ... please forgive me ... When I try to raise my thoughts to Heaven there is such convicting emptiness that those very thoughts return like sharp knives & hurt my very soul. I am told God loves me ... and yet the reality of darkness & coldness & emptiness is so great that nothing touches my soul."
Atheist author Christopher Hitchens wrote a book very critical and revealing of Mother Teresa titled "The Missionary Position: Mother Teresa in Theory and Practice". It also reveals her relationships with disgraceful individuals and that she only cared about becoming a saint someday and adhering to whatever the Vatican instructed her to do. The book was released in 1997.
- Hell's Angel: Mother Teresa by Christopher Hitchens
- The Missionary Position: Mother Teresa in Theory and Practice
- Mommie Dearest The pope beatifies Mother Teresa, a fanatic, a fundamentalist, and a fraud. By Christopher Hitchens
- The squalid truth behind the legacy of Mother Teresa
- The Missionary Position (book)