As Thich Nhat Hanh writes in Peace is Every Step, p60:
"Every time we practice mindful living, we plant healthy seeds and strengthen the healthy seeds already in us. Healthy seeds function similarly to antibodies. When a virus enters our bloodstream, our body reacts and antibodies come and surround it, take care of it, and transform it.
This is true with our psychological seeds as well. If we plant wholesome, healing, refreshing seeds, they will take care of the negative seeds, even without our asking them.
To succeed, we need to cultivate a good reserve of refreshing seeds."