When I watch this film (Repulsion) today, I realize that I didn't really progress much in directing actors. It's just question of giving them the right ideas and then they pick it up. I really learned most of it watching movies; watching movies at the film school where we saw it day and night, three a day sometimes. Going a lot to the movies. More you see, more you become critical of the actors' performances and having started as a child actor, you know, I obviously had some kind of talent that combined with lot of movie going helped me to be able to recreate behavior which seems natural and original.

What makes acting interesting is when the reaction is authentic, real, and yet original...that's not what you actually anticipate as a reaction. ...That makes it more interesting.

Roman Polanski
from Repulsion audio commentary track