We learn that you can shave your butthole and that when you live with someone you have to be yourself all the time. Your SO (Significant Other) will, at some point, walk in on you pooping - get over it. 

We learn that you deserve to be happy with people you’re with. 

And finally we learn that boys get to be boys and girls get to wait for boys to figure themselves out - except for the notebook that’s a super progressive love story.