The Big Bran Hypothesis - S1-E2
Other mistake: Leonard is awoken by the apartment door closing. When he walks into the living room the door is open. (00:08:55)
Suggested correction: He's awoken by a door closing, not necessarily the front door. He could have heard Sheldon closing his door.
Other mistake: Leonard says that it's 2am when his door is knocked on, but when he opens his door to confront Sheldon, his window outside shows daytime light. (04:12:00 - 04:25:00)
The Creepy Candy Coating Corollary - S3-E5
Other mistake: When Sheldon signs the entry sheet Stuart claims he wrote "Die Will Wheaton Die." But he was only writing for half a second to a second, he could never have written all that in the time frame.
Other mistake: Sheldon would not have been able to crawl straight along the window ledge to Leonard's bedroom due to the layout of their apartment. Leonard's window is round a corner from Sheldon's.
The Herb Garden Germination - S4-E20
Other mistake: When Sheldon and Leonard are playing Archery on Wii Sports Resort, Sheldon presses the Z button on the nunchuck controller to fire the arrow, which is incorrect. When Leonard plays, he holds the Z button as he prepares to fire, then releases the Z button to fire, which is the correct controls. (00:03:00)
The Rhinitis Revelation - S5-E6
Other mistake: When Mary is rubbing VapoRub on Sheldon's chest, she makes a comment that last time she saw that there was no hair, to which Sheldon replies "Yeah it filled in last year." In Season 1, Episode 11, Penny rubs VapoRub on Sheldon's chest and a very clear remark about chest hair was made. Season 1 for the show was 4 years ago.
Suggested correction: Sheldon is probably joking when he tells Mary his chest hair filled in the previous year.
He doesn't understand sarcasm, hence, doesn't know when to be sarcastic.
And nearly all instances of Bazinga are not used in a funny circumstance. Indicating poor judgement and lack of knowledge regarding jokes.
They were funny to him. And to the audience.
The Countdown Reflection - S5-E24
Other mistake: Raj doesn't get over his selective mutism until the end of season 6. However, he very prominently speaks during Howard and Bernadette's wedding without alcohol or meds. In the season 6 episode where he finally does speak without any assistance, Penny makes a big deal about it so it's shocking when he does it here with no big shocks.
The Higgs Boson Observation - S6-E3
Other mistake: Just before Amy video chats Sheldon there is a shot where she is wearing glasses, and when the camera zooms out she isn't.
The Parking Spot Escalation - S6-E9
Other mistake: Sheldon tries and fails to move Howard's car at the start of the episode. However if you look closely the car does roll backwards even though the handbrake is applied.
Other mistake: When Howard, Stuart and Sheldon are ringing the bells, they are ringing differently from the "code" (00:16:45)
The Spoiler Alert Segmentation - S6-E15
Other mistake: When Leonard and Sheldon are about to make up, you see green lights flash in the hallway. The next shot you see the hallway and it's completely normal.
Other mistake: Leonard says he had a growth spurt after his high school prom. In "The Cooper-Hofstadter Polarization" he told Penny that he still had all his clothes he owned since the eighth grade, after his last growth spurt.
The Clean Room Infiltration - S8-E11
Other mistake: When Howard, Leonard, and Raj are arguing in the clean room, Howard says that Leonard is jealous because Howard and Leonard used to be "best friends until Koothrapali came along." Yet, in the earlier seasons, we know that Howard and Raj already knew each other when Leonard met them for the first time and brought them back to the apartment to play video games. Meaning they couldn't have been best friends before Raj came along.
The Convergence Convergence - S9-E24
Other mistake: Howard believes he's being followed by the government, when it's actually Leonard, Penny, and Beverly in their car. The shots from Howard's car show only Leonard's silhouette. The other two do not appear as silhouettes.
The Paintball Scattering - S12-E11
Other mistake: When Penny and Leonard are in the paintball shack, Leonard won't shoot Penny because they are too close and it would hurt. Penny doesn't believe him, but eventually, he shoots her in the chest, and she says in pain, "You're right, we're way too close." But Penny should already know what this feels like; she was shot in the chest from close range in a paintball shack by Sheldon in one of the earlier seasons when she shot his cushion with a paintball. So this feeling shouldn't surprise Penny in S12.
