I absolutely adored this book, and am completely in love with John Greens writing style and humour. I particularly appreciated the way John Green didn't sugar coat the life of the modern teenager. Being that i was a teenager not too long ago myself, I can safely say yes, teenagers play pranks and ditch class, smoke and drink and have sex. Hell, they've even been known to drink and drive.
I do wish, however, that the teens these days were as intelligent as these. Oh well, what can you do? Besides, books don't have to be 100% real. It's a made up, fictional story. Half the fun of reading is being able to enter a world or scenario that you may not get in real life.
Anyway, back on to topic - I love this book and it is actually quite enlightening.
If you haven't already, definitely give this a read. Ps. WARNING: You will both laugh and cry, cry, cry (or am I just a wuss? ;P), but like any good psychological experiment, John leaves you debriefed and resolved, curing your new found Bipolar disorder by the end of the book.