Why do my guest keep leaving from my party?

[Leto85]

I don't have late night, so I'm not sure if it's something to do with that.
However, I can suggest getting the Legendary Host lifetime reward. I found it makes my parties more successful.

I wonder if you still will think the same way after reading this guide: http://www.carls-sims-3-guide.com/articles/party.php   

[Pam]

I've had guests leave parties early, too.  Sometimes they just have someplace else to be, like a job.  Even at night Sims have to leave to go to work.

[Leto85]

I've had guests leave parties early, too.  Sometimes they just have someplace else to be, like a job.  Even at night Sims have to leave to go to work.

Mine only leaves if they are not happy. And almost aways that have to do something with toilets... or the lag of it.
Therefore, build a toiletroom, right besides the fiesta room. 10 just for man, 20 for woman, just to make sure that everyone has a place to empty whatever they need to empty. Works fine by me.
I mean, works fine by me ingame members. So don't take me wrong.