A Solar Calculator, a Game Ball, and a Cheerleader's Bosom - S1-E5
Continuity mistake: When Connie is playing the slot machine at the end, the wheels land in a set order. She then has a chat with someone and then goes to spin again, but the wheels are in different positions than before. We see Connie through all of this, and she doesn't spin between the two instances outlined here. (00:17:30)
A Therapist, a Comic Book, and a Breakfast Sausage - S1-E4
Continuity mistake: When George Sr. is first trying to help Sheldon, who is choking, he has his left arm under Sheldon's body. When the shot changes, his left arm is across the back of Sheldon's neck. (00:00:40)
A Therapist, a Comic Book, and a Breakfast Sausage - S1-E4
Continuity mistake: When Connie is talking about her date possibly wanting some more of her, George Jr. has a fork in his hands. When the shot changes, his hand is at his mouth without a fork in it. (00:04:55)
A Therapist, a Comic Book, and a Breakfast Sausage - S1-E4
Continuity mistake: When Connie, George Jr., and Missy are sat in the car, eating ice cream, Missy goes from holding the spoon to not holding it and back to holding it, depending on the camera angle. (00:14:40)
A Therapist, a Comic Book, and a Breakfast Sausage - S1-E4
Continuity mistake: When Sheldon points out how big the sausage was that he choked on, he holds his hands up in the air to symbolize this. From the shot behind Sheldon, his hand is not visible. (00:03:00)
A Therapist, a Comic Book, and a Breakfast Sausage - S1-E4
Continuity mistake: When Tam moves his stuff on the lunch table, his arms are around his lunch. When the camera does an instant cut, his arm is no longer around his lunch. (00:03:30)
A Solar Calculator, a Game Ball, and a Cheerleader's Bosom - S1-E5
Continuity mistake: When George Sr sits down to talk statistics with Sheldon at the kitchen table, his beer bottle keeps rotating in his hand. Note the label. (00:08:30)
Continuity mistake: At the start, the cards in Sheldon's hands keep changing between shots. (00:00:40)
Rockets, Communists, and the Dewey Decimal System - S1-E2
Continuity mistake: When Tam mentions the Ku Klux Klan, Mary has nothing on her fork. When the shot changes, she's suddenly got some food on her fork. (00:15:40)
A Broom Closet and Satan's Monopoly Board - S3-E2
Continuity mistake: George invites Mary out to dinner on Friday. But while they are at dinner, Sheldon is attending his college class (with Dr. Linkletter) - which meets on Thursday.
Jiu-Jitsu, Bubble Wrap, and Yoo-Hoo - S1-E17
Continuity mistake: When Mary arrives at the bowling alley and is talking to Brenda, Brenda's hands are constantly changing between instant cuts. In some shots she's holding shoe freshener and in others it's shoes. (00:13:15)
A Tummy Ache and a Whale of a Metaphor - S2-E12
Continuity mistake: When Sheldon comes round from his op, the way he holds his cup, and the way the straw faces, changes between shots. (00:09:30)
A Stunted Childhood and a Can of Fancy Mixed Nuts - S2-E10
Continuity mistake: When Paige arrives for a sleepover, Mary closes the door, and her hand is by her waist. When the shot changes, her hand is now down against her leg. (00:04:10)
A Crisis of Faith and Octopus Aliens - S2-E3
Continuity mistake: Just after the opening titles, Mary is preparing a salad when the phone rings. Between the shot of Mary and Connie and the shot of just Mary, the position of the items in her hands changes rather drastically. (00:01:50)
A Sneeze, Detention, and Sissy Spacek - S1-E13
Continuity mistake: When the principal gets the paddle out of the drawer, he holds it in two hands. But as he goes to sit down, he is only holding it in one hand. (00:02:30)
Gluons, Guacamole, and the Color Purple - S1-E19
Continuity mistake: When Sheldon startles Connie in bed, Connie has her hands up by her head. Shot changes and her hand is now across her chest. (00:15:20)
Continuity mistake: Missy's blond and blue-eyed like her mother, Mary, but in The Big Bang Theory, she's brown-haired and brown-eyed.
A Brisket, Voodoo, and Cannonball Run - S1-E7
Continuity mistake: The root George Sr is buying is different to the one he hands the shopkeeper. Note the thickness. (00:10:15)
Answer: Some people just have a dislike for someone that can't be explained. Could be as simple as the way he's dressed.