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)
Jiu-Jitsu, Bubble Wrap, and Yoo-Hoo - S1-E17
Continuity mistake: When Sheldon is wrapping bubble wrap around his torso, it goes from neat to messy between long and close shots. (00:04:50)
Answer: Some people just have a dislike for someone that can't be explained. Could be as simple as the way he's dressed.