Christianity in my belief adopts pagan practices, like changing the sabbath, ripping off pagan holidays and passing them off as their own. Christmas is a combination of the Virgin Birth, Saturnalia, Winter Solstice, and Yule. All of those except the Virgin Birth are pagan. Do not even get me...
Theological reasons, and it was a several year long process. It started when I stopped celebrating Halloween and continued until I felt that Christianity is no longer for me. One of my mantras is this: One must question everything, even God Himself. :)
Judaism is my religion so I like it, Christians believe in a Christ, Muslims believe in freedom of religion (Surah 2:256), Hindus invented yoga, and Buddhists are mindful.