The mother and son interaction on Mother's Day is a spoof on a similar one in the film "The Grapes of Wrath," released the same year.
"Tain't funny, McGee" refers to the tagline from the long running radio show, "Fibber McGee and Molly."
The joke about Thanksgiving being on different dates for Democrats and Republicans is lost on most people today, but before 1939 Thanksgiving was not a fixed date, it relied on a Presidential Thanksgiving Proclamation each year. President Abraham Lincoln began the national holiday in 1863 and most people were used to Thanksgiving being the last Thursday of November. In 1939 (the year before this short was released), President Franklin D. Roosevelt changed the date of the national holiday, much to the disagreement of many states' governors and their citizens. This change added an extra week of holiday shopping, which pleased business leaders. The move was quite controversial and it wasn't until the end of 1941 that Congress passed a law to settle the dispute and establish the "fourth Thursday" of November as Thanksgiving Day.
Tradition holds that on Leap Day (February 29, which occurs once every four years) women may propose to men.
On the mother's living room table is an old fashioned lantern slide viewer, the forerunner of the popular mid century toy, the View Master.