It might sound stupid, but sometimes (at least for me) I find joy in bringing others joy. I do my best to compliment strangers around me when I notice that they’ve done something special to make themselves look nice or if I really like a piece of clothing. I go out of my way to bring/send treats to my coworkers or friends when they have a special day coming up. It’s a reminder to them (and to myself) that the world is what we make of it, so why not do what we can to make it better? Joy is not a zero-sum game - something that takes me an iota of effort to do can bring huge returns in happiness of others.