After dealing with issue for many, many years...I put the 'survivors' in a bin and match them similarly and get a 'Unique' new pairHow one of the socks is always missing?! Always losing a pair. The washing machine eats them, I'm sure lol. It's a mystery.
Or... Then I just wash a sock without its pair, oops!
***this solution only works when you buy similar style, otherwise it makes one look like a goof to the less aware