] Also, does anyone know of any famous/infamous examples of bad service during the Regency or were people always that polite?

Yes, coaching inns varied in their service. Stops while the horses were being changed would take about half an hour, and hungry travellers might order some food. There are tales of meals delayed deliberately until the coach was due to set off, so there would not be enough time to eat, although the food was paid for. The same joint of meat would thus be brought out time and again and sometimes turned green in the process.

I imagine Lady Catherine, being most attentive about such matters, would expect instant service with fresh food.