Coulda, woulda, shoulda - S4-E11
Continuity mistake: Carrie is sitting at her laptop eating a blue ice pop. She takes a bite from the top then holds the stick with the rest of the ice pop in between her teeth while she types on the laptop, we see a shot of the screen. When we go back to Carrie she is eating the rest of the ice pop which is impossible because just 2 seconds before it was still attached to the stick. She didn't have time to bite it off the stick because she was using both her hands to type.