I found this idea in a Slashdot history, and tried at home. Every time I had tried to shave smoother (by doing several passes, as just one was too spiky), I ended with either red itchy skin (and not really smooth), or the same with little scars, bleeding.
Olive oil allows me to make any number of passes, without red skin (a little blood, but it is not a problem if the skin feels good). But the first pass hurts as hell, beware. Then it gets softer and smoother. I repeat between 2 and 4 times, and then get a really hot shower. I don't put any soap or anything to clean the oily face, I just let the high pressure hot water clean it. Also, the bubbly water falling from my hair sure helps clearing without irritation.
Afterwards, be sure to have some soap nearby, to clear the oil spilling in your sink.