A Stupid Argument?

I just parted with a friend due to a quarrel on religious belief. She is a fervent christian while I am sort of atheist but liberal in talking of religious beliefs. We have talked of many subjects and I have been very candid with her not concealing anything and speak straight from my heart so to say.  She has been very talkative and has been quite a good listener at times. But this time it involves the subject of belief in relation to a phenomenon in her mother's critical illness that led to her stressing her strong belief in God stating that there was an evil spirit which caused her mother's ear to produce strange noises and peculiar sound. I on my part strongly denied there was any evil spirit whatsoever and stressed my stand as an theist while she maintained there was evil spirit and that God exists and so on and so forth.  In the heat of argument, she emphasised her viewpoint of God and everlasting life while I of course maintain my atheist stand until at last she broke off the argument by hanging up and thus ended our friendship right there. I don't regret it either because I still have to be honest to myself and to others in the matter of beliefs.