Whty Do You Know That?

Let's go back once more to this one. It's the converse of "Auto Mechanics to Quantum Mechanics" where you provide everyone with those tidbits of useless knowledge you have stored away for no good reason.

My contribution:

Oak trees don't drop their dead leaves in the fall.

The word "stoic" comes from the Greek "stoa" which means porch.

The word "set" is the most ambiguous word in the English language, having the most independent meanings.

So, what do you know and why do you know it?