A night out has a natural rhythm. When the dessert comes, you know the evening is nearing its close. When the bouncer is called to your table and instructs you to leave, you know you've outstayed your welcome.
When the timekeeper tells me time is up, that's not the dessert arriving; it's not a signal to tuck into the last course of the meal. It's a sign that I've already overshot, and it's time to stop.