The 1978 film of A Little Night Music is widely reported to be terrible and in lots of ways this clip bears that out - the sets are dull, the costumes fussy. And yet Diana Rigg is just amazing - I saw her in Stoppard's Jumpers playing the singer-wife of the philosopher and she really is an amazing singer, for an actress.
Also, there is something slyly slashy about the later stages of this...