Continuity mistake: Penny throws a black iPod out the window, but when Raj comes in having found it on the ground outside he has a silver one. (00:01:00 - 00:02:45)
Continuity mistake: When Penny is squirting chocolate syrup in the ice cream container, she drizzles some on the lip of the carton, causing it to run down the outside. The camera switches to Leonard and then back to Penny, at which point, the chocolate is gone. (00:04:50)
Character mistake: When Leonard and Sheldon sit down for lunch at work, Sheldon grabs the salt and pepper and begins to shake the "shakers" over his food. However, these are grinders and not shakers. He would have had to twist the tops in order to get any salt or pepper. (00:16:10)
Continuity mistake: When Leonard is consoling Penny on the couch, the blue Afghan she has with her constantly changes position, including jumping from the floor back to the couch.
Continuity mistake: When Penny is talking to Leonard about who read her Ex's blog, she has a spoon full of ice-cream. Camera cuts and it's now empty. (00:05:00)
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