I will always be a Catholic as its history and supernatural teaching reveal it the true and only Church founded by Christ, but I understand the anger many feel toward the Church, primarily due to human practices that claim to be teaching, primarily the practice keeping women from the priesthood.
This poll from Pew Forum reveals reasons people leave the Catholic Church.
I believe women should be priests and wrote a book about it—as do most Catholics in America as this story from Catholic Culture reports— and there is more biblical reason for it than there is against it, but the institutional church is run by men and they appear unwilling to change many practices that have long outlived their time.
In his excellent book, Garry Wills wrote a great chapter about the issue, which begins thus:
“When Pope John Paul II visited the United States in 1979, he was met everywhere with enthusiasm verging on adulation. But when he reached Washington, and spoke to a gathering of nuns, he was met also with respectful dissent. Sister Teresa Kane was no young hothead or rebel, but the superior of the Sisters of Mercy and the elected head of the Leadership Conference of Women Religious (not a wild or radical group). Appointed to greet the Pope, she took the occasion to make a public request that “half of humankind” be recognized as worthy to “be included in all the ministries of the Church.” The Pope answered that the Virgin Mary should be the nuns’ model, and Mary was not a priest.
“Elsewhere the Pope gave the reasons for women’s exclusion that Paul VI had written four years earlier, objecting to the Anglicans’ decision to ordain women priests, an objection that the Congregation for the Doctrine of the Faith (the old Holy Office) followed up with a solemn declaration, Inter Insigniores (1976). The church has no power to ordain women, that document said, because Christ made only men his original apostles. Despite an official position that now welcomes scriptural scholarship, the Vatican can revert, when that is useful, to biblical fundamentalism of the most simpleminded sort. The twelve apostles were men, so all priests must be men. But the twelve apostles were married, and the church authorities decided they could change that—in fact, John Paul says that the church cannot go back to the original situation on this point. Saint Peter had a wife, but no modern Pope or priest can. Are we to say that all priests must be converted Jews? The twelve were. Are they all to speak Aramaic? For that matter, if we are to make the gospel situation binding now, we should observe that the apostles were not priests themselves.” (pp. 104-105)
Papal Sin: Structures of Deceit. (2000). Garry Wills. Doubleday: New York.