Perhaps I've been lucky so far; most of the criticism I've received has been broadly constructive. One person I asked to detail what he/she was criticising and I was surprised how many flaws there were.
Like the rest, I write for fun, but I do want to get better; so if someone shows I use to instead of too somewhere I'm usually grateful (though I don't go back and change it) because I'll look out for it next time.
Trouble is once you've read a story a couple of times, you know what it should say and miss the mistakes.
The scoring is a bone of contention, but perhaps I'm not quite aiming at the core audience. But I'm writing for fun (mine) as well as appreciation so I doubt I'll change.