in reply to Socks with Sandals:

I missed the option:

cool, healthy & convenient!

Nothing else can be worn between April and September.
Except for some business dates maybe...

For younger guys with feet looking better than mine, it is ok to skip the socks. But I'm sure nobody would like to see my bare feet peeking though sandals

The rest of you may switch on the aircondition and fire the global warming!