Actually, more like 3.5. 
 I know this is people's least favourite of John Green's. And while I can see why this can be so, I don't think it deserves all the bad press that it's getting. It's by far the funniest of the bunch (sure, not HAHA funny, but happy chuckles, and that's good enough for me). And I LOVED Colin! Lots of people don't, but I do, I truly do. I like the contradiction that is him - a nerd to the core, but c'mon, he gets some pretty real good action from the ladies too - and the words that come out of his mouth are such a delight to read. I love it when he starts speaking random foreign languages too (I mean, that's pretty neat right?), especially the conversations between him and Hassan. This book was also ladened with many mind-blowing facts that I have never known, and I think it made me somewhat smarter. 
 So yeah, I don't think this is the worst of John Green's book.