Growing up with a sibling is an experience like none other. That experience entails a combination of fights and good times, times where you try your best not to inflict any bodily harm on each other and times where you can just laugh for hours. Overall, it's pretty cool.
John and Jen tried to encapsulate this experience, while showing the effect that growing up has on the relationship between siblings. Jen, the older of the two siblings, goes off to college where she establishes her own identity. In the meantime John remains home, missing his sister but becoming his own person too. When they are reunited John feels that Jen has abandoned the family and has become a person he can never have a close relationship with. He feels that Jen has changed for the worse and embodies all that he and his father are opposed to.
John and Jen instantly reminded me of my brother and I. My brother has gone off to college and when he returned, I was also surprised to see the person he has become. After a whole lot of new experiences, meeting new people, and doing new things, he became someone who was not the brother I knew before. When he visited home, we argued a lot at first. He had a new perspective on things and formed strong opinions that countered my own. One argument got so intense that we did not speak for weeks. Days before he had to return to school, however, we warmed up to each other and began to talk about the good times, the days when we had bunkbeds and would wake up at 6AM on weekends to play video games with each other.
I realized that all those fights were stupid. We still have our major differences but we can not neglect all the good times that we shared. In the show, Jen realizes the same. (**spoiler**) Unfortunately for her, it was too late. People who you had long meaningful relationships with will change over time; it is inevitable. We lose close friends and gain close friends. However, I think that there is a place reserved for siblings and a close bond will always exist.