Yes programming you subconsciousness works! It is a technique called VILD: http://en.wikibooks.org/wiki/Lucid_Dreamin...ppendices:_VILD that use the same thing to be lucid.
Even if dreams often is quite abstact and works in symobls dream signs can be the store for instance. Every time your in the store you do reality checks intensive and try to be aware of what is happening during the whole shopping tour.