Fiorella clears her brain for sleep at night by replaying scenes from Big Bang Theory and pondering future plot twists for Leonard, Penny, Sheldon, Howard, and Raj.
Maybe Leonard could marry Penny and move into her apartment across the hall, which could set up a lot of new plot angles, like Sheldon trying to find a new roommate. Ultimately, of course, he'd settle on Amy Farrah Fowler, which would lead to its own complications. Then only Raj will be left without a mate so he'd have to be somehow relieved of his problem of not being able to talk to attractive women.
A baby or two, a la I Love Lucy could be added along the line.
And then there are all the relatives we have yet to meet--Leonard's father, brother, sister, aunts, and uncles; Penny's mother (or is she dead?) and brother; Sheldon's brother; Raj's four other siblings besides Priya; Howard's long-lost father.
Com'on, guys. There's enough fodder here to extend this sit-com till Howard finally gives in to peer pressure and gets a Ph.D.