There are cons and pros in watching the movie first before reading the book. And watching it first prior reading is always a bad choice. 
 Here's the thing: I cried, laughed and smiled real hard with Hazel and Gus' story. But dang, that was all when I watched the film! And it's not nice. I ain't gonna say that it was my friend's fault for inviting me to see the movie first. But what she did was not nice. Anyway, I'd decided to read the book long after I saw the film so I could at least forget some scenes (Hey, it took me three years to read the book!) But nothing happened. Everything was still vivid. And this, I solemnly swear that The Fault in Our Stars would be the last book that I will watch the movie re-enactment first before reading it. Although the film itself was a solid job. 
 Anyway, for the book review. I know it was a sad and tragic story. And I was supposed to cry. But that was the side effect of a cancer story. You cry and pity the characters. And let them know that it was beautiful because someone died. And also because, of course, you cried. 
 But I am not saying it was a bad book. I said that because I, well, become aware of. TFIOS was a really good book with a good story. It had beautiful dialogue, clever and witty characters (which we don't really have in real life because of this. Is. Fiction.) It also makes me look at death and dying in a different way. I liked how well John Green made Hazel Grace snarky, who always express heavy and meaningful yet waggish prose. And Gus, sweet Gus. I am still wondering why he needs to die. But that's oblivion. 
 All in all, it's a fast read that will not just break your heart but will do its part to glue it again. 
 "Some infinities are bigger than others." Time to enjoy yours.