In short, tea stain?

Not knowing what your sister won't like , it's kind of hard to say what can be done. My suggestion is to maybe pull the colors together in quilting with a variegated thread or a quilting motif in a single complementary thread color. Sometimes the quilting and thread color can change the entire look of a quilt. Good luck!

I'm curious why you say she won't like it.

There are all kinds of ways to change the appearance of the quilt, but it comes down to what she doesn't like about it. Applique circles, Flowers, stars & moons or complete pieces of another fabric to add interest & perhaps, cover the one you & she don't like. Add another applique color which could be a "zinger" in any design you want. Or use fabric paint to add dimensional squiggly lines after quilting on the part you think she won't like. Or would she like some lace or beading added? You are looking at a one dimensional top now. Quilting with dense quilting in some areas, then less in other with contrasting threads can change the whole appearance.

My suggestion would be to finish the quilt, show it to her, then let her help you decide how to improve it to her standards. If she doesn't like it, change it to be something you could love. And next time you want a quilt made....go out to the Internet & find a wonderful quilt with colors & a pattern you like. It really makes the color coordination process a lot easier. FYI... I am a beginning quilter too & really am no good at picking more than 3 or 4 colors. I love all the wonderful quilts we see on QB & they have inspired me. Let them inspire you!

I think it looks great. A picky person is very hard to please, if not impossible. Things like that are better left to her to pick for herself. That's what I think.

Have the quilt finished as is. It is a beautiful piece of work and trying to change anything now will be very difficult, expensive and time consuming. I wouldn't think twice about giving it to your sister - she may just love it! If she doesn't, take it home and buy her something else. It is just one of those lessons we quilters learn - unfortunately there is no fix. Be sure to smile and tell the quilter what a great job she did as it is very hard to make a quilt for a paying customer - lots of stress.

This is 100% great advice. And I agree it is beautiful. Give it with love and pride.

These are my thoughts exactly. I'd let my sister choose her own bedding and not try to do it for her if she is THAT picky. (But don't often brides want to pick out their own first quilt).

Keep the quilt and of course, pay for it without mentioning the fact that the colors are not what you were thinking.

Oh my goodness, what a dilemma! I agree that there really isn't anything to be done except be kind, be gracious. Pay her and keep it for yourself or to give as a gift to someone else. Next time, go shopping for the fabric yourself and have another one made.

this is a great reply and one that I was thinking. Remember that this is a gift from you (and your boyfriend's mother -- even if you "reimburse her for the materials and her time -- what about her efforts!) . Hopefully your sister will have the same thoughts. The quilt is lovely. Even if it were not my favorite colors, I would love it. The pattern and color combination is great.

I don't think that is harsh
 

You can't please all the people, all of the time, and some people you can never please. If she is so picky it is probably the best to let her pick her own quilt from a store and you keep the beautiful, individual, one of a kind quilt that Sharon has made. I know which I would prefer but then I am old (and wise?) and can appreciate the work that goes into these things.