Aww, I'm glad to hear this! I forgot I had pointed that out to you. I'm kind of surprised I was that ballsy, because even though we all know I'm a Grammar Nazi, I usually try to avoid being a Grammar Nazi in reviews, unless the author asks for that kind of a critique. I never want to inadvertently hurt someone's feelings, especially a friend's. But I guess I knew you could take it without getting offended, and obviously, I thought the story was good enough that fixing that one thing would take it from good to great. And as someone who has been reading and sometimes proofreading your writing for the last five or so years, I can honestly say I see a huge difference too! You don't switch tenses like that at all anymore! Most people I've pointed out grammar issues to don't fix them or can't fix them because they just really don't get it, so thank the Grammar God for writers like you! There's still hope for the rest! LOL
In all seriousness, I think constructive criticism can be, as it should be, very helpful. I also know that it can be tough to hear, especially when you're a newer writer or haven't gotten much before. Once you figure out how to accept it and learn from it without getting offended, you'll be able to use it to become an even better writer. It just takes time and experience for some people to get to that point.
I think the key is asking yourself, what is this person trying to tell me, why are they bothering to tell me, and are they right? Usually people only take the time to give constructive criticism when they think the story has potential, unless they're reading it because they were required to (judging, reading challenge, author request, etc.). If the writing's hopeless, why even bother leaving a review? I only give constructive criticism when I can sandwich it between genuine compliments about the story. If I can't say something nice, I just don't say anything (the Thumper rule). As far as whether or not the reviewer is right, some concrit could be subjective, if it's based on their opinion on something that happened in the story, but if it's about grammar, plot inconsistencie s, or misinformation, chances are, they're right, and you should listen to them and fix what you can or at least try to learn from the mistake (like, when in doubt, look it up!).