I think Tarantino put mysteries into Pulp Fiction for the same reason Scott wrote this post -- the mind likes to make connections where there are none. Scott did this quite deliberately, to entertain us both on the meta-level and on the level. I suspect Tarantino added inexplicable elements so that we as the audience would be entertained by speculation. There's nothing underneath.
If you want to see what happens when the writers lose their nerve and try to explain everything, watch Lost.
If you want to see what happens when the writers lose their nerve and try to explain everything, watch Lost.