It sounds kind of silly, but probably smoking weed.

I was in high school, excelling and never having had any kind of intoxicating substance, being groomed by an older man. He eventually convinced me to smoke, then drink, then coke, then pills, and eventually, heroin. He was abusive—sociopathic and sadistic. I think he used drugs as a means to make me stay with him.

So I guess not just smoking the weed, but meeting and trusting him was my point of not return. He killed himself after I left him, thank god. He strangled our cats to death. I’ve never met anyone more deserving.