Continuity mistake: Jennifer Aniston and Kevin Costner are at the bar after she meets "B.B." after the conference in San Francisco. As he said "I can't be your father", Kevin Costner's left hand suddenly jumps to his chin as the shot changes from a side shot to one behind him.
Continuity mistake: In the bathroom scene where Jennifer Aniston is taking a shower and having a comical heart to heart with Shirley McClain, just after McClain says "And, don't call me grandma" she approaches the shower and screams Kevin Costner's name. There is a quick but very noticeable change in the shower curtain/towel position as it is lifted by McClain along with a vocal shift. Quick, but it's there.