Lots of get-things-done experts tell you to set aside dedicated time to tackle your most difficult tasks. You need to choose a time when you're mind is clear and you've got the energy to concentrate and deal with details. For me, this is the morning.
When I have to go to meetings first thing at work, it wrecks the rest of my day. The meetings usually don't get out until 10 AM. By then, the coffee rush has worn off and drinking more coffee has minimal effect. I usually come out of meetings with new tasking and new issues to consider, cluttering my brain with new odds and ends. Contentious meetings require plenty of water-cooler talk rehashing who said what to whom. Nothing of significance gets done the rest of the day. Oh sure, little tasks get knocked out, but the big ones lie around until tomorrow and the day is shot.
I vote we delay all meetings at work until after lunch.