It has been interesting making these socks.  The top ones are as the yarn comes from the ball.  I didn't worry about what colour I used to start the second sock.  
The colourful ones were made from lots of random (but of course) carefully picked - well they looked good together... I chose the colours as I knitted along.
The creative side of me says that I love the quirkiness of the mismatched effect, but the organised side says that I should knit other socks to match.  But that would mean I would have to knit 4 more socks, and I think I would be bored with that...  

... But I this wool left over.  If I started with a different colour..., or added a new colour, it could be interesting what I produced.  
No I think I will make some in a totally different colourway. Got to keep the creative juices flowing.
These socks are available in my shop