Black is Black

Black is black, I want my baby back.
It's grey, it's grey, since she went away.
Oh-oh, what can I do??
'cause I-I-I-I-I,
I'm feelin' blue.

So the song by Los Bravos in 1966 went.

My version...

Black is black, I want my black socks back.
They're blue, they're blue, what shall I do?
Oh-ho, what can I do??
'cause I-I-I-I-I,
I'm seein' blue.

Some time ago, I bought a pair of black socks to go with my black shoes. In fact I bought a few pair of them. I also purchased blue socks to go with my blue pants somewhere along the line.

Now the other day, I put on my black socks, black pants and black shoes. Later on that day, Barb commented on my wearing Navy Blue socks with black pants. Huh? I didn't want to admit it, but they did look Navy Blue with my black pants. I hadn't noticed this before. So, the next time, I wear the same socks with my blue pants. Now they looked black. ??? What's up? Is this some kind of chameleon sock that I have that changes it's color so as not to match what I'm wearing? I'm not sure what to wear these socks with any more.