I found the Loving Kindness practice challenging in that I had to focus completely on other people. It caused me to lay down my personal feelings towards the people whom I know that have wronged me in the past.  I had to draw from my inner resources in order to do this.  It felt good to focus on others instead of myself and cultivate those life-giving thoughts of goodness and blessing.  This is something I will need to practice regularly, especially when I struggle relationally. It would be easy to just give in to negative feelings towards that person, and wallow in self-pity and anger. These emotions are all self-centered and bring me no real benefit-- they accomplish nothing except to make me feel more miserable!  
I would recommend this practice to others, but I am not sure everyone would be open to it. People tend to be steeped in their way of dealing with things, and this is a radical new approach. You have to want to change. I can at least share this option with them; then the choice is up to them.

The concept of "mental workout" involves taking time daily to practice contemplatively.  Even as we become stronger physically when we work-out and exercise, our spiritual and psychological muscles will develop as we put into practice Loving Kindness and the Subtle Mind. Research has shown that we can benefit greatly through regular meditative practices.  A well trained mind can influence our physiology, hormonal system, and immune system.  Our brain circuitry can be altered so that we can dwell in a sense of well-being and peace.  Our memory, attention, perception, and imagery can even be enhanced.  This causes not only short-term change, but also long term structural change.  Through constant mental training, negative emotions can be reduced that cause worry, fear, anger, confusion and doubt.  The positive emotions of love, patience, kindness, openness and honesty can be enhanced. Ultimately our goal is decreased mental distress and greater resistance to physical disease.  Our healing capacities can enlarge and we can dwell in a sense of well-being. Isn't this what everyone is longing for? 

The only way I can foster this type of mental workout is to make time for it in my schedule the same way I make time for my physical workout.  I need to make and keep it a priority!  They say it takes three weeks of an activity to make it a habit, so this is my goal. When I start to reap the great benefits from these contemplative practices in my life, I won't have to force myself to practice them, I will want to "dwell" here more and more.  Hopefully it will become a part of who I am and the fruit that results will touch those around me and make my little part of the world a better place! :)