I would say it was the friend who found religion and simply wrote me out of her life.

Your (friend?) asserted a classic example of the outgroup homogeneity effect based assertion. If you are not us, you are one of "them" and "they" are all evil. A tool in the brainwashing indoctrination process for cults like Christianity.

As for the worst thing a believer has said/done to me? Nothing comes to mind but the list is likely long enough to fill a typed page. I engage anyone who attempts to asserts any religious supremacy to my rational world view. They usually greatly regret making any theistic founded assertion Is I tend to expose their statements as being void of integrity.

I remember sitting in a car with my step-dad and our pastor at the time. I was probably about thirteen-years-old. We were in a parking lot, and one of the stores in front of us was a liquor store. I said out loud, "I wish an earthquake would come and knock over all those bottles." I really just wanted to see what it would look like.

The pastor turned to me and said, "There's something good about Ben after all."

Thats dreadful. You needed love and support at that time.

That was high-octane, first-order gaslighting, and as a free bonus, it was cruel. Way to go, Team Jesus!

I can't top that one, I'm afraid, but if I have to recall some fundamentalist trope that ultimately caused me the most pain in a real-world situation, the award would go to a pastor in my early adulthood that fed the divorce taboo doctrine at a time when I was in a clearly abusive marriage to a person who was clearly mentally ill: "If you have faith, god makes even bad marriages right". This and similar bad advice kept me in a marriage for 15 years that I should have ended after about 6 months. And I could go on and bore you for many paragraphs with other knock-on effects of staying in that marriage too long; let's just say it's been the "gift" that's kept on giving.

That's just a horrible thing to say to someone mourning. Also when theists say stupid shit like that they don't realize how that drives people away from religion.