The Bridge - S1-E10
Revealing mistake: Agent Coulson turns the steering wheel several times despite the car being on a straight street.
Chaos Theory - S3-E7
Revealing mistake: In the shot where Lash hauls Rosalind over the parapet to later drop her, you can see that he is actually lifting a mannequin as its legs very fluidly bend backwards while it is being dragged over. (00:32:00)
Revealing mistake: When Ruby flips her mother (Hale) over in her room, it's obvious that Hale is played by a stunt double.
Chosen answer: Coulson believes he was resuscitated then sent to Tahiti to recuperate. "A magical place," he calls it. But in the "Agents of S.H.I.E.L.D." episode "The Magical Place", Coulson, through a mind-reading machine, learns that he was treated by S.H.I.E.L.D. and a fake memory of Tahiti was placed as a "mask" of sorts over the painful memory of the operation, which involved a drug seemingly of alien origin to repair the damage, coupled with a lot of morally dubious surgery.