When the mind wanders, it takes you to wonderful places, average places, horrible places. Places that do not exist. Places that often determine your joy or sorrow.
The only thing that is real, though, is the here and now. What you are doing in this moment, the context you have around you, the possibility for you to decide to change the activity and the context. And your mood.
A wandering mind can take you places, but train the capacity to come back to reality at will.
If you fall in love with an outcome, you will never notice that the world around you is moving, that the context is ever changing, and that the outcome, in the end, does not provide that sense of reward you had anticipated.
If instead you fall in love with the journey, you are in the present, here and now. You see the changes, you notice the details, you are awake and ready, you have a place to fall back to when the unexpected becomes reality.