Mondays are certifiably awful for me as well. For some reason pretty much ALL of the meetings I'm involved with at work take place on Mondays. AND I'm the analyst so I'm expected to speak in a somewhat coherent way.

I TOTALLY hear you on the irritability front. The 2nd meeting I had today I even went to far as being snappy with my boss. (I later felt the need to apologize.) Kept trying to talk to correct what people were saying and EVERYONE kept interrupting me.

You are so not alone. I'm only "productive" being I'm pretty much forced to be that way.

In terms of TRUE unproductivity though, I have this stupid superstition about Tuesdays. I'm not even kidding.