I recently saw some updates that improved the interface far beyond the standard client for Yahoo Pool. This program now tells you where every ball will go, giving the user a color-guided image of the outcome of any shot as you set your aim.
Yes, with YAimer it really is impossible to unintentionally lose any Yahoo Pool game. However, I think YAimer makes Yahoo Pool more fun if you turn down the aimer and just play with the new graphics and snappier interface.