(I also hate how long so many of my sentences are. That's one thing I'm certain I want to work on.)
This same sort of "Sayer's Remorse" happens to me a lot during and after face to face conversation, too. I'm chugging along, being my amusing, interesting, exciting, dynamic, empathetic, loving, witty and shiny self, and then all of a sudden I notice a facial reaction on one of my friends... a not totally agreeing and not totally connecting sort of look. I can't tell if it's a negative reaction being hidden, or a non-reaction being portrayed perfectly, or what. In that kind of moment, and often for long after, I keep having to ask myself whether I was being a dick.
I don't fully trust my own ability to judge whether I've been a dick. That's what it comes down to.
Maybe I need some kind of online polling system to let my friends guide me more directly. Maybe I'd find out that I should be getting off my ass and ceasing all this "journal writing" activity, and instead spending my time travelling from friend to friend, paying them money, doing their cleaning and cooking, and occasionally driving vans back from Mexico for this one friend of a friend of my friends.
Ah, fantasies. You have to love them.