It's disappointing that one of the most romantic leads on the show didn't find romance. You could easily argue that the character who completed the most personal growth during the entirety of The Big Bang is Raj. He went from a spoiled adult, living off mom and dad, and couldn't even talk to girls, to someone who knows himself well enough to walk away when a relationship doesn't feel just right.
A lot of people were annoyed that Big Bang spent a good deal of the last season of the show demonstrating conflict between Leonard and Penny and her wanting to remain child free. In the last episode Penny revealed she was expecting and was good with it. This unexplained 180 didn't sit well with a lot of people.
Most people probably don't want their relationship judged for romance during the years when they have very small children, but these two have seemed especially unhappy over the years.
Odds are if you're a die-hard fan or have watched a few seasons of the show on and off you know the last names of many of the characters. Guess what? Penny's last name is never revealed through the course of the show.
Stewart slowly got his life together over the course of the show. When the series ended, he had moved in with his girlfriend Denise, who also works at his store. Hopefully these two can work together to create a successful business model that will allow him to win at love and a career.
Since the growth happened over 12 seasons the big changes in Sheldon Cooper may not be as noticeable to some. Go back and check him out in season one to see if you feel any differently. The impact of his friends, family, and partner Amy have changed him into a virtually different, better person over the years.
We were introduced to Young Sheldon for a couple of seasons before The Big Bang Theory called it quits, but would another spinoff work? Which characters would you focus on? Frasier aside, very few other shows get spinoffs that are nearly as successful as the original show, but with the quirky characters on Big Bang, they may have a shot.
Sheldon and Amy (or Shamy, if you will) have already practiced pseudo-parenting techniques on their friends in the form of an experiment, but will they have kids? The unpredictability of children would not be welcomed by either potential parent, but man they would make some really smart kids.
Howard was proudly raised by his single mom. When he finds an old letter from his dear old dad, it was an emotional episode which caused many to wonder, who is his dad? While Howard chose to not actively look for his dad, maybe one day dad will eventually cross his path. Perhaps dear old dad will want to meet his grandchildren.
Was the Nobel Prize the success swan song for Sheldon and Amy or are they going to go on and do more? After reaching this professional milestone there is very little that either could do to compare. Perhaps they will focus their efforts on other things – Flags with Friends, Amy becoming a professional harpist? The sky is the limit for this duo.
On the last episode of the show we saw the elevator in working order for the very first time (aside from flashbacks from when it was broken).
Throughout the show we meet Leonard's mom routinely as she shames him about being her least successful child. Through this we learn that he has two other siblings, a sister without a name who is a scientist working to cure diabetes and a brother named Michael who is a tenured law professor at Harvard.
In Big Bang Theory the old expression, 'children are best seen and not heard' is flipped on its head since routinely we only hear the babies cry (complete with pipes that match those of Howard's late mother). It isn't until an episode in the final season that we see the children for the very first time.
Real estate is expensive in California, so it's understandable why these friends were renting well into their thirties. But absolutely everyone in the show has a good to great job with an excellent salary and benefits by the end of the series. You'd think at least some of them would pool their money together and stop renting.
Howard only having a master's degree as an engineer is often the butt of Sheldon's jokes. Although he's a very successful engineer and even went to space, we also know that he's competitive. His attempting a doctorate came up a few seasons back, but it never went anywhere. Maybe when his kids are older, Howard will get his PhD, even if it's only to rub it in Sheldon's face.
Penny wanted to be an actor, but that didn't work out. Soon she discovered she was good at pharmaceutical sales but didn't really have a passion for it. Sure, she's making more than Leonard by the time the series is over, but that doesn't mean she's happy. Penny seems to have sacrificed more than other characters in the show, which makes it hard to know whether she'll really be happy for the long haul.
In 2015, Howard's younger half-brother shows up on his doorstep.
Amy (and Mayim Bialik) both serve as inspirations for young women in academics and science. After winning the Nobel Prize, perhaps Amy could start a mentorship program or give TED talks.
You'd need a time machine or an elaborate dream sequence to have characters from The Big Bang Theory show up on Young Sheldon, but that doesn't leave it out of the realm of possibility. Perhaps the actors will come in and play other characters completely unrelated to their time on Big Bang, just for a lark.
Although it's an ongoing joke when Sheldon says, "I'm not insane, my mother had me tested", some of the more clinical things about Sheldon's unique way are never addressed on the show. Jim Parsons has said that he played Sheldon like he is on the autism spectrum, which has caused some controversy, since a diagnosis and the social responsibility is never addressed. You'd think a cerebral person like Sheldon would want answers as to why he is the way he is. Only this question is never asked, let alone answered.