After Renee hits her head in the shower, falls unconscious and wakes up on the floor, blood is seen to have come out of her temple. The blood is running down along her face, and staining her shirt collar. Since she fell down quickly after hitting her head, the blood should have been running toward the back of her head.
When Renee is the receptionist and greets the model with the fierce lipstick, the straw in the water bottle appears and disappears.
When Renee is walking at night towards the Lily office, a number of extras passes Amy. When Amy stops at the corner, a female extra with salt and pepper hair passes her again,
When Grant is mentioning Renee's pigtails, the shot showing the back of her head shows both pigtails in front. But, when we see Renee from the front her left pigtail is back over her shoulder.
Avery (Michelle Williams) says she has an MBA/JD from Wharton. Wharton is a business school with no JD program. Her JD would have to be from Penn.
Amy Schumer's character keeps mentioning that she hopes to work at Lily LeClaire's headquarters on Fifth Avenue. However the headquarters is shown to be in the Bank of America Tower, which is on the other side of Byrant park, on Sixth Avenue.