First off: I am not a misanthrope. Really.
Still, I find the long-lingering party to be one I wish to escape from. It has nothing to do with the company being charming v. crashing bores, the quality of food and wine, etc. It has simply to do with time. I am sometimes the first to call it a night. I like leaving earlier than most.
If I am invited for drinks and dinner, at a certain point post-dessert, post-coffee-and-conversation, I will get internally fidgety and want to close out the evening, or at least my participation in said evening. Three to four hours is sufficient in my opinion, to have discourse with one's fellow humans (See the thread with a similar stance and discussion, esp. the OP's musing on time: http://chowhound.chow.com/topics/567036).
How to exit, gracefully? I tried after 5 hours of a potluck last weekend to say farewell, only to be met with detours of thought and the long Midwest-Scandinavian goodbye. Forty-five minutes later, we were on our way, very tired.
Is being tired an adequate excuse to exit a get-together? Is three or four hours a sufficient time, or should one take other cues (i.e., waiting for someone else to leave and then making one's goodbyes on those coattails?) Is time of evening relevant - say, at midnight should we all still be gathered, or is it 10 pm or 2 am? Do other attendees find the first-to-go rude?
I love my friends and family, but I have this niggling little responsibility called my "real life," along with all its schedules and responsibilities. I will happily join in on social events, but the open-ended quit time is a problem for those of us who do not want to be among the last to go, or be made to feel *guilt* upon leaving first.
What do you attendees think of the first to leave? Gauche? Wise? Somewhere in-between? Or are you among the ones making an early exit? So curious.