The One With Joey's New Brain - S7-E15
Character mistake: After Susan Sarandon slaps Joey the first time, after he tells her that her character is dying on DOOL, she turns away and right before she is off camera she smiles, instead of maintaining her anger. (00:06:05)
Origin of Iron Man: Part 1 - S1-E11
Character mistake: When young Tony Stark is telling his father that their helicopter's anti-flak chip didn't kick in, he acknowledges that it was his fault by saying he blew it. When his father corrects him and says "No Tony, we blew it. Stark and Son," Tony defensively says "The anti-flak chip failed, it's not my fault," completely contradicting what he said seconds earlier. (00:14:00)
Behold, a Distant Star - S2-E10
Character mistake: When Sue is brought out of surgery, her father can be seen wearing a watch. Surgeons don't wear watches or any other kind of jewelry when performing surgery, as they can't be sterilized and can also get in the way of gloves. (00:05:00)
No Good Deed Goes Unpunished - S9-E13
Character mistake: Dr. Corday finishes assessing a gun shot victim, then goes to the next trauma room to assess another. The steady cam follows her. She makes sure not to contaminate her gloves on the door, opening it with her elbows, but then goes straight to touching the next victim. Of course, in real life, she'd change gloves first. The shot never changes, so there's no chance of her changing gloves off camera. (00:12:30)
Character mistake: Geraldine's name changes from "Boudicca Geraldine Granger" to "Geraldine" but with multiple middle names from Mary Poppins with the surname "Granger."
Kiss My Bum - S4-E10
Character mistake: Before Ellen invites Perry to thanksgiving there was only going to be seven for thanksgiving and yet whenever someone is asked about how many there are going to be at thanksgiving they answer eight.
Six Forgotten Warriors Chapter 4: The Six Fight Again - S5-E5
Character mistake: When the Red Skull reemerges from the vortex, he sees Chameleon and acknowledges him as his stepson. However, only moments before this, Kragov explicitly stated that the Chameleon was more like an adopted son to the Red Skull.