When I first went out with my husband (donkey years ago :-D ) I noticed he had bits and pieces of mismatched coloured thread on his clothes. Sometimes it was on a button, and sometimes on a hem which had become loose. He told me it was his old nanny who had mended his clothes. It showed me that here was someone who was not fussy about his clothes. He still isn't but I am. I remember removing the coloured threads and replacing them with matching ones! Lol!
But with my quilting, I make do with whatever colour is nearest in shade.