I read somewhere that in the "olden days" people used only white or black or RED thread for quilting. I use up spools of whatever I have when doing scrap quilting, especially red because I have a lot of it. This was all given to me.
My star quilt was dark blue with light colors in the stars. I should have switched to white or light when I sewed the seams that were more light than dark. Didn't think of that until it was finished, and the dark thread showed on the light parts. A smaller stitch might have helped also.