I posted a few months ago about Spectre, a boulder problem in California that I consider close to perfect. Last week I read a blog post about a one shoed ascent. Terry Paholek did Spectre wearing only a left shoe so that he could use his toes to cam and pull on the footholds.
You can see from the photo on the left (from the Bishop Bouldering) how important the right foot is.
Terry Paholek, Spectre V13, Bishop, CA from chalk on blocs on Vimeo.