Can non-theists appropriately feel existential gratitude?

Does it make sense for non-theists to feel gratitude for their existence? The question arises because gratitude is typically thought to be directed towards a person to whom one is grateful. Hence the theist may be grateful to God for their existence, experienced as a gift. But can the non-believer feel something similar without being irrational? Can there be gratitude for existence but not to anyone? After analysing gratitude and how we can best understand the idea of non-directed gratitude, I discuss the conditions that need to apply for non-directed gratitude to be appropriate. I end by discussing whether theism provides a psychologically richer and more satisfying framework for understanding existential gratitude.