Chade-Meng Tan, in Tools of Titans:
In many of my public talks, I guide a very simple 10-second exercise. I tell the audience members to each identify two human beings in the room and just think, “I wish for this person to be happy, and I wish for that person to be happy.” That is it. I remind them to not do or say anything, just think—this is an entirely thinking exercise. The entire exercise is just 10 seconds’ worth of thinking.
Everybody emerges from this exercise smiling, happier than 10 seconds before. This is the joy of loving-kindness. It turns out that being on the giving end of a kind thought is rewarding in and of itself… All other things being equal, to increase your happiness, all you have to do is randomly wish for somebody else to be happy. That is all. It basically takes no time and no effort.
During working hours or school hours, randomly identify two people who walk past you or who are standing or sitting around you. Secretly wish for them to be happy. Just think to yourself, “I wish for this person to be happy, and I wish for that person to be happy.” This is the entire practice. Don’t do anything; don’t say anything; just think. This is entirely a thinking exercise.
If you prefer, you can do this at any time of the day for any amount of time. You can also do it at any other place. If there is nobody present, you can bring someone to mind for the purpose of this exercise.
I tend to do a single 3- to 5- minute session at night, thinking of three people I want to be happy, often two current friends and one friend I haven’t seen in years.