I have come across most of these cases myself. Although frustrating, I do understand some of them such as the first tag and the URL. I usually edit in notepad first to avoid the worst of it. I'm particularly careful with tags and titles. I haven't mistakenly posted yet, but I've mistakenly re-steemed.
I guess if I post by accident, I'll edit it to a funny joke, a BTC price update, the local weather and maybe a random pic...so much trash posts these days, doing this will probably be an average post.