My boss was back in today. I only saw her once in passing and in as cheery a voice as I could muster said "Hi! Welcome back!" She grumbled something in return, but I didn't care. All that mattered was that I sounded like I was happy to see her again.
The trash talk going around is that she chewed out the Assistant Library Director and her Administrative Assistant because they didn't open her mail while she was gone. Not that she asked them to open mail for her -- she didn't. And around here, you just don't do anything unless asked directly and even then you run the possibility that you will still get chewed out for actually doing something.