punctuation: what are you?

I have a facination for grammar and punctuation. But I understand that the common person doesn't. So let's have some fun and I'll teach you some things. (I apologize if you already know some of this.)
The two most frustrating misuses of punctuation.
1. The apostrophe in words that are not possessive.
ex."I have a lot of book's."
In this sentence books is just a plural noun and is informing us that I have a lot of books. Now if I were to say this it would be the correct usage of the apostrophe.
ex."Mary Beth's books are well taken cared of." Here it's telling whose books they are. Mine.
2. The semicolin in sentences that should not be joined. Now I know every writer avoids semicolins like the Black Plague but really it's quite simple to use if you just remember two simple rules.
      1. Semicolins can't be used to join two sentences that do not have similar messages and that cannot stand alone as a sentence.
ex."When I read a book; it gives me great pleasure."
When you're trying to communicate you wouldn't leave off your sentence with " when I read a book."  It leaves the listener hanging to find out the answer. What happens when you read a book?
Now here's an example of a proper way bonuses a semicolin.
ex." I love to read; I love to write."
Here these two sentences make sense and don't leave the reader hanging if they were separate but they also have similar structures. It tells what I love.
       2. The second rule to using semicolins that if you have a huge list with a lot if commas already a semicolin is used ti separate the different items being listed.
I hope this little bit information has enlightened you and helped cousin becoming a better writer. Punctuation is needed to help effectively communicate, but if not used correct it actually does the opposite.