I have had to add a little Cremo or Kiss My Face to some soaps to develop a super-lather if the soap won't lather by itself. However, if I can't figure out how to lather it without the additives, it does not stay in my den.

Most soaps do contain oleic acid (the primary fatty acid in olive oil), but if you add too much, it can kill the lather. I make up a preshave oil once using olive oil, grapeseed oil, sunflower seed oil, but I could never get a great lather using my hard water, so I stopped using it.