If I say something it's one of three things

- it's what I think is true, which means it's my opinion,

- it's something I don't think is true, but I want people to think it's true, in which case it's a lie

- or I'm being sarcastic or ironical or whatever, and I as expecting other people to realise that I mean it that way.

So I can see the point of saying "in my opinion" for one particular sentence in a post. What does it imply about all the other sentences?

I think if you say something here that's you'd be wary of saying face to face because of the hostile reaction you might get, that's just cowardice. It should be the other way. There are things I'd say face to face to people that I'd never say at a distance, because face to face you can say hurtful things in a way that doesn't hurt. I think a basic rule should be, never set out to hurt as such. There might be times when you need to destroy someone, but that's a totally different thing.