The Barbarian Sublimation - S2-E3
Continuity mistake: When Penny explains she has bought the game, her grip on the laptop changes. (00:06:50)
The Barbarian Sublimation - S2-E3
Continuity mistake: When Penny sneaks into Sheldon's room at night to ask him about the online game, she leaves his bedroom door half open. But when she leaves, the door is shut. (00:07:35)
The Barbarian Sublimation - S2-E3
Audio problem: When Penny walks out after Sheldon helps her with her game, we see Leonard start the music but the speaker doesn't start vibrating for over a second after the music has started. It should have started at the same time. (00:07:40)
The Barbarian Sublimation - S2-E3
Revealing mistake: When Sheldon gets the sword for Penny in the game, Penny walks out and you can see the laptop isn't switched on. (00:07:55)
The Barbarian Sublimation - S2-E3
Continuity mistake: When Leslie and Sheldon are talking to Dr. Eric Gablehauser in his office, in one shot Eric throws a piece of paper onto the desk behind him (next to the computer.) Through the rest of the scene, this piece of paper keeps changing position. (00:09:00)
The Griffin Equivalency - S2-E4
Continuity mistake: In the opening scene, just after Howard says, 'Creepy good or creepy bad?', there is a shot where Howard is holding his food, even though Leonard hasn't given it to him yet and it isn't there in the shot before or after. After Leonard gives the food to Howard, the exact same shot is used after he says, 'I'm not necessarily talking about the food', so the shot was taken from there and it is shown twice. (00:00:25)
The Griffin Equivalency - S2-E4
Continuity mistake: When Raj asks the guys who's going to the party on Saturday night, Penny's grip on the martini glass she has changes between shots. (00:10:20)
The Griffin Equivalency - S2-E4
Continuity mistake: When talking about wanting a griffin, the bottles and strip of paper on the table keep moving between shots. (00:16:00)
The Griffin Equivalency - S2-E4
Continuity mistake: When discussing what qualities their new friend should have, the container Howard has changes position instantly. (00:17:20)
The Euclid Alternative - S2-E5
Continuity mistake: When Penny turns on to Euclid Avenue, the car behind her just vanishes into thin air. (00:03:50)
The Euclid Alternative - S2-E5
Continuity mistake: When driving down Euclid Avenue, the background is constantly changing between shots. In one shot it's a busy main street and in another it's a suburban street. (00:04:50)
The Euclid Alternative - S2-E5
Revealing mistake: When we see Sheldon and Howard on the scooter, look in the back of the mirrors to see the reflection isn't moving. Indicating the bike isn't moving. (00:07:40)
The Cooper-Nowitzki Theorem - S2-E6
Continuity mistake: At the start as Leonard says about being able to talk to women, he puts his hand on his drink. Camera cuts and now his hand is back by the edge of the table. (00:02:50)
The Cooper-Nowitzki Theorem - S2-E6
Continuity mistake: The way Ramona holds her drink in the cafeteria changes between shots. (00:03:50)
The Cooper-Nowitzki Theorem - S2-E6
Continuity mistake: When Ramona starts talking to Sheldon in the cafeteria, the way Sheldon holds his knife and fork changes between shots. (00:04:00)
The Panty Piñata Polarization - S2-E7
Continuity mistake: At the start when Howard is asking about the house, the pencil in front of him keeps moving on the table. Note the point and the edge of the table. (00:02:30)
The Panty Piñata Polarization - S2-E7
Continuity mistake: When Leonard talks to Penny about having to live with Sheldon he has his hand up to his chest. Camera swaps to a side view and his hand is not in front of his chest any more. (00:07:30)
The Lizard-Spock Expansion - S2-E8
Continuity mistake: The way Leonard holds the can of Diet coke before he puts it down changes between shots. (00:00:25)
The Lizard-Spock Expansion - S2-E8
Continuity mistake: When Raj says Star Trek 5 is worse than Star Trek 1, his hands are outspread. Camera cuts and now they are clasped together. (00:04:15)
The Lizard-Spock Expansion - S2-E8
Continuity mistake: When the guys are in the Mars Rover test room, the time displayed on the large digital clock seen behind Howard jumps about inconsistently between each shot. (00:07:50)
Answer: Because Raj's selective mutism seems to be caused by women that Raj sees (on some sort of conscious or subconscious level) as a potential sexual partner. An attribute that wouldn't apply to either his sister or mother.