The problem with day-of-the-week-socks is that it takes a while to find the right pair of socks in the morning. You could just wear the first pair you pick up, but does anyone do that? For some reason I have a nagging feeling that wearing the ‘wrong’ socks would be in some way confusing. Hands up anyone who checks their feet to find out what day of the week it is. No? I didn’t think so. Just as well, because if anyone checks my feet today they might forget to have pancakes later!
One day I might just go crazy and wear two different days at the same time!!!
Notes from a small field 
I’m with you on the avoidance of wearing the wrong day socks on the right day. But I’ll bet you that kellypuffs would use her socks as a day-of-the-week calendaring mechanism if she could.
And she would probably make the socks using a patented Kellypuffs sock quilting device…