Why are Christianity and occultism irreconcilable?

Occultism, both in subtle and patent forms, is everywhere in our modern societies. A workmate tells you about a ouija seance she attended (and what she saw there, to her surprise), another tells you about a reiki treatment she's receiving, a close relative becomes a yoga fan... These are real examples I've known. I am a Christian believer (Catholic, to be precise) and I know the basic things about this issue: they are deviations from the virtue of religion, because they turn to "false gods" (demons, "energies", esoteric entities, ...) and forsake the True God; and they're also an exercise of pride, in which you try to obtain certain powers that belong only to God. Sadly, I find that these reasons are not enough to convince most occultism-practicing people, even those from a Christian background. So, specially for these cases, I feel I need more arguments in my arsenal and a deeper knowledge of the subject (apart from praying harder). Therefore, here it goes: why are Christianity and occultism irreconcilable? Thank you. Note 1: all denominations are welcome. Let's make it ecumenic. Note 2: bonus attention for charismatic approaches :) . EDIT I'll keep the question as it is, with all that it entails. To be useful to me, it requires a full scope, so denominational scoping would not make sense. But before making any decision, please read this Meta post of mine .