Eventually, you get to the point as a knitter when you mostly know what you like and definitely know what you don't like. Life is just too short to knit awkward patterns, ugly colours or displeasing yarn.
On a recent trip to Mary Maxim I purchased two skeins of their Gemstones brand in the Sapphire colour. On the skein it appealed to me so much, looking like random undulations of all my favourite jewel tones. However, as I unwound it to cast on, I began to suspect that it was stripes, not random at all. A quick click on Ravelry to view project photos proved me right. This has long colour repeats that make thick, solid sections and there is a one particularly bright colour - a turquoise that was hidden inside the skein - that pops vividly, not blending at all with the other darker tones of purples, burgundies and teals.
What to do? The yarn is otherwise very nice so I hate to waste it but I just knew knitting it as it was would make me cranky. My solution was to go through both skeins,cutting out that turquoise and spit joining the pieces back together. Now I am knitting off both balls at once, starting each at a different colour point and switching between them every two or three rows. It's producing the random look I wanted. A lot of work and trouble? Perhaps. However the result is totally worth the effort.