I've got the opposite attitude. If you read it you'll know what all the self-help authors are ripping off (and a ton of contemporary non-fiction is functionally self-help) and you can be inoculated against the bullshit. If you have a critical, reflective attitude towards reading it, it's all grist to the mill. And Carnegie is a better writer than most in the genre.

I wouldn't be worried about a book ruining you. You're not gonna keep up with bullshit that goes counter to your values anyways, unless you're avoiding something, which is something that a book isn't culpable for.

Tbh I am reading a kinda terrible BDSM guide at the moment and while I find some of it insightful, I find it more useful to understanding what the fuck people on Fetlife are talking about. Like there is a veritable epidemic of One Twue Way on there scattered among the groups and now I got some understanding of it.