Freaky Friday - No Socks
The morning Tess and Anna switch bodies, in the scene where Tess (in Anna's body) is trying to get Anna (in Tess's body) out of bed, Tess has trouble getting Anna out of bed and has to pull her feet in order to try to get her out. While doing this, Tess falls, and it is clear (if you pause it) that she is not wearing socks. However, if you rewind to the part just before Tess grabs Anna's feet, she is wearing socks.
VCR or DVD player, a remote, a pause button, eyes.