Which wolf to feed?

I'm not given to airy-fairy, arty-farty New Age bollockspeak but occasionally - just occasionally - I read something that makes me stop and think for a second (and then continue on my normal, ramshackle way).

I read this today and I'll just leave it here because I actually quite like it:

”My son, there is a battle between two wolves inside us all. One is Evil. It is anger, jealousy, greed, resentment, inferiority, lies, & ego. The other is Good. It is joy, peace, love, hope, humility, kindness, empathy, & truth.” The boy thought about it, and asked, “Grandfather, which wolf wins?” The old man quietly replied, “The one you feed.”