If our hearts are small, the smallest incidents from others can enrage us. If we expand our hearts, we are capable of treating others with compassion and empathy.
Happiness can't be attained by fulfilling superficial desires. Happiness can be attained by being mindful. If you focus your attention on every single movement of your body and forget your eventual destination and the reason you're trying to get there, you'll begin to understand what happiness is. Same with noticing your breathing. When you focus on your breath, your heart rate will slow down immediately. Give yourself caring kindness with each breath you are taking for no specific reason, just do it. Mindfulness is about experiencing and appreciating the present moment. When we are listening to the present, we begin to notice how much beauty there is in the world. We can appreciate the joys of something as simple as a blossoming flower or a bumblebee.