Factual error: When Ben goes to Anna's yoga class, we see the very end of the class. Everyone is seated upright, cross-legged. In real life, yoga classes always end in savasanah, a pose where you lie on your back and breathe to take in all that the body/mind just did. They just had the actors seated upright to show them making eyes at each other.
He's Just Not That Into You (2009)
1 factual error - chronological order
Visible crew/equipment: In the first half of the movie, when Jennifer Aniston tells Ben Affleck her sister's getting married, a cameraman's reflection appears in a painting on Ben's left. It happens again a few seconds later.