Everyone skips a pop culture phenomena every once in a while. Maybe your friend doesn't know the words to a single Lady Gaga song or thinks Twilight is just a time of day. If you skipped the Harry Potter release parties, refused your cousin's offer to let you borrow book one, and know Daniel Radcliffe only as that guy Darren Criss replaced on Broadway, it's ok. You can catch up pretty quickly. Here are the plots of books 1-7 as tweets.
What it's aboutBook One
Harry=orphan, Harry=wizard?! Voldemort=Harry's arch nemesis, Ron+Hermione+Harry=BFFs4EVA, Voldemort vs Harry-Harry wins!, rematch to comeBook Two
Dobby says "danger!" Harry says"don't care," the heir of slytherin is petrifying!, giant snake vs Harry-Harry wins, sensing a trend?Book Three
Sirius Black is: loose-a murderer-Harry's dad's BFF-Harry's godfather-the reason Harry's parents are dead-totally innocent-a great gift giverBook Four
Quidditch :) Death eaters :( Triwizard Tournament, Harry vs dragon, drowning, Voldemort-Harry wins! Cedric vs Wormtail, Cedric lossesBook Five
Harry is moody. he wants to join the anti-Voledmort club, too young, starts teen anti-Voldy army, Umbridge=worst teacher ever, RIP SiriusBook Six
Horcroux scavenger hunt!, Ron+Hermione 4EVR? Harry+Ginny 4 a little bit, Snape is bad! Malfoy isn't totally bad, RIP Dumbledore *sob*Book Seven
Camping w/ evil fighting, Harry vs Voldemort Harry wins NO REMATCH RIP Tonks Lupin Dobby Hedwig Fred; Future holds Harry+Ginny, Ron+Hermione
Your Favorite Part Will Be
It's hard to pick one favorite moment in the series. If you're a romantic you might favor a certain pair of main character's first lip-lock, if you're into action book seven's final battle will have you glued to the page, and if you like a book that makes you cry then you might want to check out the end of book four. And five. And six. And basically all of seven.
The Cause-y Angles
Luna Lovegood is pretty awesome, from her incredibly positive attitude to her radish earrings. And while Harry and company eventually come to appreciate her bravery and loyalty, they're initially introduced to her as Loony Lovegod, not to mention everybody keeps stealing her stuff. Luna has a pretty thick skin, but the girl in your class who's being teased might not be so strong. Invite her to sit at your lunch table, or let your friends know it's not ok to tease her in front of you.
From the introduction of a slur based on someone's bloodline in The Chamber of Secrets readers learned the wizarding world can be as divided based on background as the muggle world. And as HP characters proved again and again, someone's blood does not define them. Hermione is muggle born and can kick any pure blood's butt; you should never discriminate against or underestimate someone because of their ethnicity.
Mental Health 
Maybe there aren't wizard psychologists, but by book five it's pretty obvious Harry needs some professional help with all the issues he's dealing with. Most teens don't have to contend with a toxic mess of being orphaned, raised by cruel and unloving people, experiencing multiple near death experiences, then witnessing a classmate's murder, but many do have looming problems that can leave them scared, depressed, anxious, or any number of problems that therapy can help them address.