The Grasshopper Experiment - S1-E8
Continuity mistake: When Raj starts talking to Penny after he drinks the Grasshopper drink in her apartment, in one frontal shot he lifts the drink and begins to drink but in the next shot from behind the drink is back on the counter.
The Monopolar Expedition - S2-E23
Continuity mistake: When Penny finds out about the expedition, Sheldon starts to walk to his apartment. Camera cuts to Leonard in the apartment for five seconds and then to Penny in the doorway. Behind her, you can see Sheldon walking to the apartment still. Since he was halfway to start with, he should be in the apartment by now. (00:10:35)
Chosen answer: It does. The variable cleanliness of the cab and the habit of taxi drivers to engage customers in small talk would be too much for Sheldon to handle, and not an option for him.
Captain Defenestrator