A common practice in the United States (and perhaps globally) is to take parts from different religions and philosophies, mashing them together to form a personal belief system. Doing so is extremely consumer-centric: keep the parts you like and ditch the rest; keep what is comfortable and jettison everything that make you squirm.
Making up a belief system in that manner is really little more than deciding to believe in yourself; of making God in your image, to be who you want and need him to be for your own satisfaction and comfort.
It may seem like a good approach, but it’s not. The God who is revealed in the Bible doesn’t like it when people mix religious thoughts and practices. In fact, he has some harsh criticism for them, which he shared with the prophet Zephaniah.
Speaking through the prophet, God declares his judgment against those who mix the worship of him, with the worship of stars and the worship of others gods. Mixing and matching doesn’t work in God’s book.
He is not content to have our partial attention. He is jealous of our affections and wants it completely. We must give ourselves fully to him.