Wow, writing haikus is strangely addictive! Also I'm really bored. So, I have some more:

When writing letters,
Consider your audience.
Catch flies with honey

When standing in line,
Think about the poor cashier
Trying not to snap.

Cell phones for children-
You must know they will lose it.
Who must junior call?

Teenagers send texts.
You will not add the package?
OK, I warned you.