A gift is a gesture of love. You give a gift to those whom you love. A gift is a voluntary act. A voluntary act can never be forced. Just as love cannot be imposed by force, a gift cannot happen without affection and love being present by the giver. A giver's love is reflected in whom he gifts.
Yes, these are all occasions for gifting. Gifting happens also often for no reason. It is a reminder of your love to the people whom you gift.