"The perks of being a wallflower" Character Relationship Portrayal vs Real life

Why do authors falsely portray relationships and friendship in their books? It's very frustrating to read about these friendships that last forever, then when i look at my sisters and my parents and my friendships... they mess up all the time. I am almost postive that the majority of authors just write to give us hope but really all they're really doing is setting us up for disapointment, noting lasts forever except maybe marriages but even then its inevitable. So why write about these amazing relationships? 

In "Perks of being a wallflower," Charlie, the protagonist, makes friends on the first day of school see, I find that really unrealistic, especially if you're new to the school and you hardly know anybody. Their names are Sam and Patrick and they are both seniors. Charlie is immediatly invited to one of their parties after the first week. In real life that usually takes about a month, in the beginning of an actual friendship it's really awkward and quiet, usually you are still getting to know eachother.
Later in the book, when Charlie falls in love with Sam and she tells him not to. She introduces him to a friend of hers, Mary Elizabeth. He begins to talk to her and noticing that they get along he asks her out on a date about tree days later. I am sorry, but unless you have an ENORMOUS amount of confidence, it will not be that easy to do that. Usually in reality, there are like these weird phases you go through, it's not just some type of spontaneous love at first sight like people describe in movies. Though many people describe it to their friends and then their kids, its probably more like a "woah" more than a "wow i'm totally going to marry her one day.

I guess now I understand why authors use these false portrayals. I guess sometimes readers do need some false hope, because maybe after a long chain of bad breakups and rude people they just need to believe for some odd reason that they might just have a spontaneous love at first sight moment or the best friend you can tell anything to in just a week becuase you are THAT comfortable around them. I guess it isn't so frustrating because I am one of those readers who "awws" at romantic moments in my books and movies. So now I say thank you to authors for false hope because in more ways than one you've given me a lot more than a fairy tale to believe in, you gave me the will to believe in anything.

Grapes of Wrath - John Steinback - Sacrifices

In John Steinback's book "Grapes Of Wrath" the main character Tom Joad is a man who has just been released from prison and has come to find that his family is not at their house but on their way to california in search of jobs. He then finds his family and joins them for the rest of the trip. The Joad family faces many issues during their time of their search for employment their stay in California. 
Later, a man named Jim Casy is murdered and in retaliation Tom murders the men who killed his friend. his angry brother later tells someone that Tom has killed two men and his mother then tells him to go hide. Tom then is forced to sacrifice his home with his family and leave, in order to keep them safe.