Well, here the final proof that in the morning I act by instinct and that I am not using my brains yet…
To prevent this from happening again, I will make sure there is only one set of shoes near my bed…
Guess almost none of my colleagues did notice it… or were too polite to mention it… 
ps. This is also an invitation to “the authors” not only to publish complete articles, which are very welcome of course, but also fun things like this. Let’s loosen up :-).
Really Rob, you must be kidding! It made me really laugh loud.
But to be honest, this is not something that only can happen to you!
And you walked all day with 2 different shoes? Oh my :-).
But then again, they say that wearing two different socks is a sign of intelligence. Why would that be different with two shoes?
At least the colours are fitting….. :-)