When Ali walks round the corner from her office to see the disastrous news conference about the Chinese bid on the TV, her lipstick changes instantly from pink to bright scarlet.
In the church, before Ali is knocked out, she is wearing lip gloss; after she comes to in the hospital, Ali has no lip gloss.
When Brandon sits at Ali's desk for a raise, towards the end of the film, reflected in his glasses you can see lighting equipment and Green Screen.
When Ali brings the cake to Ben's party and is about to leave and Will calls her back, she turns towards him and Adam Shankman's face with his chin resting on his hand is visible in the top left button on her jacket.
Joe 'Dolla' Barry says General Motors was founded by Asparagus Chevrolet in 1884. It was actually founded by William Crapo Durant in 1908.