>> On the door to many post offices in the US, is the following "No dogs allowed except seeing eye dogs". Who is that written for? <<

People who aren't blind and have dogs with them.

To add to your category of more whimsical "Did you ever wonder....?" questions --

Why do they put expiration dates on yogurt and sour cream? Is that the date it's going to go good?

Why is abbreviation such a long word?

Mike