I agree, with everyone else. The quilt looks great. The quilting doesn't look out of place or the wrong color. It enhances the quilt and you did a wonderful job. It is done and not sitting in a closet waiting to be quilted. Hurray! As someone else said, "we are our worst critics." If you really don't like the quilting or the thread color, remember when it gets washed the quilting will meld into the quilt and won't be so noticeable. However, I don't think there is anything wrong with the color thread you used. Pat yourself on the back for a job well done.
By the way, I often feel this way too, when I finish a quilt. I'll pick out something that I am not satisfied with and obsess about it. I'll put it away for a while (usually in disgust, LOL) and then when I see it again sometime later, what I thought was so terrible and stuck out like a sore thumb, suddenly I don't even notice anymore. I put this down with working with it so closely and wanting everything to be so perfect, that I pick it to death. When in actuality, there is nothing wrong with it at all.