I sorta feel the 'desire' to be useful all the time, it's nature to people to want to feel useful. The best way to possibly explain it is you feel more at ease with yourself and can push yourself much harder if you can prove you're useful, you often feel more energetic if you can be useful.
As for the 'kitsuu' situation, I'm about as confused as anyone else is... from what I know 'kitsune' is a type of fox. ???