Room full of adhesive tape

Picture your life as a room. One day you notice that a pipe near the ceiling in a corner is dripping. The sound of the falling drops makes you nervous and you'd like to get rid of it. So you repair the leak with a length of adhesive isolation tape and your peace of mind is back. Until the water finds his way through the glue and the dripping sound is back. Plop.... plop... plop... So you put one more length of tape around the first repair and you are quiet again. Of course your quietness doesn't last very long and you have to fix the leak again and again. That's not a great problem since adhesive tape is pretty cheap and you manage to always have a spare roll handy. It can take months, even years until you notice that that big clumsy repair slowly fills the whole room, that there's less and less space for you to live in and that the dripping comes nearer and nearer to you...

This metaphor adresses basically the same problem than the «feeding the tiger» metaphor. The hopelessness it conveys seems to me to be more «creative» since it doesn't lead to the thought «it's too late now, the tiger has grown so huge I really can't do nothing else than feeding him» clients will often buy when the «feeding the tiger» metaphor is presented.