This happened to me and my family one night. A friend joining us for dinner became demanding and rude to the waiter; as if the whole experience was a test of the restaurant and the waiter's performance.

Oddly too they waited until the end of the dinner (after the meal was eaten) to show their colors on clearly subjective matters.

My family and I sat in stunned silence.

When it was over our guest was demonstratively proud of their outburst, like "I showed them."

It was a lesson in how not to behave.