1) I learned that you should definitely open every single piece of mail that comes to your house. Because it just might be (on Monday) a notification from a job you left over 20 years ago telling you that due to changes in the pension law, you have $3752 sitting in their clutches, waiting to be claimed. Or it could be (on Thursday) ANOTHER job with a similar message about $7k!
Never contributed a dime to either as I recall, being young and stupid at the time.
2) If you accept low census, unpaid time off four times in one pay period- AND you only work four days per pay period, your paycheck will not happen.
3) I learned that you never really know about life. Or death. Or the future.