There is not much you can give to a parent on any occasion that is not redundant or not necessary. They have lived their lives, accumulated their needs, established their homes and met their own desires.
But… there is one thing they can not do for themselves. One thing that only a child, little or grown, can do for a parent.
Respect them for the attempt to raise you
Weather you have a “good” parent or one that has failed you in some way or even in all ways each one has attempted to do their best.
War, injury, illness, pain--physical and emotional, too much intelligence or not enough, too much work or not enough work, economic excess or money problems, other duties imposed by outer circumstances, duties imposed by negative behavior of other family members, difficulties with other adult members of the family, religious or philosophical differences, dislocations, deaths that may cause mourning depression that lasts too long for others comfort, destructive habits, inabilities and incompetence, incompatibilities, disappointments, discouragements, are just a few of the mine fields they had to walk through as they were trying to do their best for you.
Some did not make it through, trauma caused PTSD in some making it imposable to be OK for you, the death of their own parents may become too much for them to bear, the loss of a job, the loss of their own dignity through intolerance of others, the pain of their own frail lives may have rendered them less than perfect.
But they tried to the best of their ability.
When it is your turn to be the parent I only hope your children realize this.