As a counterpoint, I find myself thoroughly drained after any meeting that goes for an hour or more. Put me in a two hour meeting first thing in the morning and I'm not going to produce anything useful that day; I'll pretty much be zombified for the rest of the day.
I figure it comes down to extroverts (recharged by interacting with others) vs introverts (drained by interacting with others).
I think everyone should agree that marathon meetings suck. Perhaps 45m max, with people free to leave if it's no longer relevant to them, is what I'd advocate.
I thought my word choice might bring up the intro/extro-vert thing, but I think someone needs to be a pretty extreme case to be flustered by a (reasonable length) meeting with people they already know and hopefully like. I don't really buy it.
I figure it comes down to extroverts (recharged by interacting with others) vs introverts (drained by interacting with others).