The first of April

"The first of April is the day we remember what we are the other 364 days of the year."
~By Mark Twain~

"The first of April, some do say,
Is set apart for All Fools' Day.
But why the people call it so,
Nor I, nor they themselves do know.
But on this day are people sent
On purpose for pure merriment."
~Poor Robin's Almanac (1790)~

Q: Why are people so tired on April 1st?
A: Because they just finished a 31-day March :-)