I ran into some trouble as a result of having relationship conversations over email, because when I had as much time as I liked to redraft things before sending them, I found my reason and conscience tended to prevail over my desires

God yes - I still do that, and not just in the relationship context. I guess I've kind of overlearnt the lesson about not replying to email while you're cross, so I wait until I can bite my tounge and agree with what was said before replying at all - which I suppose avoids lots of arguments, but isn't always the best thing to do.