First off, let me start this by saying I'm not thinking of anyone in particular. But I've had my share of them, I've been around for 10 years. It happens.
In the beginning those things used to get me so low I'd literally go weeks before I could write anything. I'd question everything I wrote, would start to listen to every negative comment and let it dictate to me what type of writer I was. But I've learned... and it's taken me a while to understand this... I am not what I write!
So what if someone doesn't love your work?
They are every bit entitled to their opinion and you just have to live with it. That's what this business is all about. Harsh but true.
For an example: Stephanie Meyer has sold like gangbusters, her books have been turned into films and yet there's plenty of people who HATE her stuff. So what you think.. she's just a flash in the pan. Fine, let's look at a writer of classic literature, taught in schools, colleges, MOST readers would tell you she is their favorite author of all time. Jane Austen, author of such notable classics as P&P, (that's Pride and Prejudice for the few of you still living under a rock *wink*) Sense and Sensibility, and my personal favorite- Northanger Abbey. But go on to Amazon reviews, there's at least 100 people who would rather burn it than read it.
So what's my point with this post? Just this. Learn. Learn from them. Listen, I never send my stuff out to get read with the need to be told, this was divine, an instant classic, you write sooooo much better than me, I'm not worthy... while those things are nice, you cannot learn from them. In fact, once the dust settles and you can sort out the feelings from the critique, it's often the really harsh critique from the person (who you know HATED it) that will give you some great insight. Something obviously turned them way off, try to find what that is, stew on it... and you might be surprised to find it's got merit.
Besides, writing is all about drawing out emotion from the reader. I'll take hate over antipathy any day of the week. ;) Just means I'm getting closer.