Cherry-picking in such a biased way in order to favour a placebo over rationality shows emotional and mental immaturity, is unhealthy and could possibly lead to more harm IMO. Delusion itself is more harmful than not all other things being equal IMO. Wishful thinking isn't good. Belief should be based on what you think is true not what you like or dislike because you're unwilling to be consistent in your beliefs if you find it unattractive to do so. IMO. Not all delusion is harmful but I think a lot of it is. And, a question: who would you rather be in the company of - someone who is deluding themselves or someone who has a clear grasp on reality?
And, most may not 'follow their book in full' as you say - but many do. And many cause a lot of harm because of this - and more so has it been the case throughout history when literal interpretation was more common. There are plenty of harmful effects of religion that has come from people actually consistently taking it literally. And consistently taking it literally is actually following the religion fully as opposed to ignoring the bad parts - so the more consistent you follow it - the more harmful it is.
EvF
And, most may not 'follow their book in full' as you say - but many do. And many cause a lot of harm because of this - and more so has it been the case throughout history when literal interpretation was more common. There are plenty of harmful effects of religion that has come from people actually consistently taking it literally. And consistently taking it literally is actually following the religion fully as opposed to ignoring the bad parts - so the more consistent you follow it - the more harmful it is.
EvF