If your typescript comes back to you in your self-addressed stamped envelope and it looks like the whole thing hasn't been read, it probably hasn't, because it isn't very good. If your reader doesn't feel compelled to turn the first page, she's not going to read to the end.
But before you start sticking knives in your publishing assistant voodoo doll consider this: when someone tells you that your sample chapters don't set her heart and mind on fire, it doesn't mean that your work won't sparkle for someone else. A couple of months ago, a photographer friend of mine took the jacket photo of an author for a forthcoming title from a major house. I had rejected the book. Twice.
I get in trouble every time I suggest to my romance-writing friends that editors probably don't read every word of every submission--not even the query letters. "That's not very supportive," someone will always say, causing me to wonder yet again how warm fuzzies could be more important to some writers than actually learning how this industry works.
Publishing is a business. Editors don't read manuscripts to encourage writers, but to find books they can make money on. Facing that reality is the first little bump on the road to publication. Get over it and get on with your journey.