Moondram Pirai (1983) (left)
Sridevi was incredible as an adult who regresses into childhood, but it was Kamal Haasan who won the National award that year for best actor.
The last scene, when he tries his comic antics to catch Sridevi's eye, will tell you why.
Apart from the mind-blowing performances, there's also director Balu Mahendra's cinematography and Ilayaraja's music.