Plot Hole: In Season 3 Episode 17 "The Precious Fragmentation", the guys fight over the One Ring from Lord of the Rings. The guys decide that the last one holding the ring gets to keep the ring. In order to try to get Sheldon to let go of the ring, Raj and Howard attempt to insult Sheldon's mother Mary Cooper. Sheldon is not bothered by it as he describes Mary as being a "kind, loving, religiously fanatical, right-wing Texan, with a slightly out of scale head and a mild Dr Pepper addiction".
However, in Season 3 Episode 1 "The Electric Can Opener Fluctuation", when Sheldon ran away back to his mom's house in Texas, Mrs. Cooper is seen drinking a can of Pepsi.
Plot Hole: In Season 2 Episode 19 "The Dead Hooker Juxtaposition", Alicia moves into the apartment upstairs above Leonard and Sheldon's apartment. However, after this episode Alicia is never seen or heard from again. Whatever happened to Alicia?
Character Double Standard: In Season 5 episode 7 "The Good Guy Fluctuation", Leonard is considering cheating on Priya with comic book enthusiast Alice. He tells Penny looking for advice and Penny criticizes Leonard saying "Your not one of those guys are you"? Its funny that Penny would criticize Leonard for considering cheating when later on in Season 7 Episode 9 "The Thanksgiving Decoupling" it was discovered that she was dating Leonard while being married to Zack. In the Season 4 finale she also tried to have sex with Raj and has been seen naked by Sheldon.
What doesn't make sense... throughout the course of the series it is constantly stated that the guys have never had girlfriends, and if they do they're not attractive girls. However, every one of the guys have pulled super hot women at different points of the show. How am I supposed to believe that these guys are nerds who can't get girls when all they have gotten are hot girls. Look at Leonard's track record with women. He's gotten Penny, Priya, Dr. Plimpton, and Alice.... yet we're supposed to believe he can't get a girl. The women that the guys have dated over the course of the show completely contradict their alleged "inability" to get any girls let alone hot ones. It doesn't make sense.
What doesn't make sense.... If you notice during the series that despite the fact that they live in an apartment complex, they never actually pass any other apartment neighbors walking up or down the stairs.
