There are a few potential reasons for this:
- People are generally more rested and in a better mood in the morning, so they may be less likely to lash out at someone over a minor issue.
- As the day goes on and people get hungrier, they may be more likely to get impatient or irritable if their food takes a little longer than expected.
- Alcohol consumption can often contribute to rudeness, so people who have been out drinking the night before may be more likely to act out in a restaurant setting the next day.
Of course, this is not always the case and there are always exceptions to the rule, but in general, rude customers tend to start showing up later in the day.
