As adults without young children to take care of, we have left twice.
Once dinner was scheduled for a certain time, was very, very late. We had told the hostess that we had to leave at a certain time because of an uncle's funeral. She said fine. As I remember, I did help with the prep and serving, Lucas and I gulped down a serving of meat and a dinner roll, and left on time. I didn't do any cleanup.
The look on their faces was priceless. We did get to the funeral on time, and had a good meal afterwards. All interactions with them have been a little better scheduled since then, even when it didn't matter.
The second time was after a cousin's funeral. Oddly, there was no meal afterwards - which might be the norm in some places - so we were invited to the other cousin's house for supper. No plans were made. They wandered around for a while trying to decide whether to go to the seafood place or run out for Chinese and a couple of other options. After an hour of no decisions, we just thanked them, gave our condolences one more time, and left. We had an 8 hour drive. Burger King never looked so good!
So, yeah, hungry adults get cranky, too. In CakeBeret's case, her focus in on the child,