In no particular order...
When sat on, a chocolate chip granola bar looks enough like something else that a complete stranger will come up to you and tell you your 3 year old has an 'issue'.
Sippy cups with straws flow like a river when opened at 36000 feet. Note to self, unscrew lid slightly before opening to release air pressure.
A 3 year old can and will talk for an entire 3 hour flight.
$3.50 for a regular ole (small) cup of coffee is not too much money to spend at an airport for coffee if you are traveling with 4 children.
If your flight gets canceled, run to another carrier as fast as you can. You might be able to get your tickets transferred to another airline.
You can never pack too many wet ones.
Shout Travel Wipes remove smeared chocolate that looks like something else on the pants of a 3 year old.
Do not put an electric kettle on a hot stove burner, the plastic will melt and flames will be seen.
It is almost impossible to explain the concept of homeschoolings to a foreign Asian woman who can hardly speak English.