system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why are some holidays on certain days of the month, like Christmas, while others are on certain days of the week, like Thanksgiving?
gpt
If you're in the USA, some, like Labor Day and Thanksgiving, are celebrated on certain days by Federal government decree.  Others, like Christmas, are acknowledged by the doctrine of whatever party is celebrating them (such as in the Catholic liturgical calendar), and (EDIT) popular enough to have the Federal government acknowledge them with State, County and Local governments following shortly after.