I have a sister in law who most would consider to be the rudest, most in grateful person on the planet. She never EVER thanks anyone for gifts, we never know if she liked something and would throw out gifts given to her kids if she didn't like them. Out of respect for my brother I would never ignore her birthday or Christmas. Over the years I have come to know that if I give her a gift that I am proud to give someone then I am okay with the universal karma and she can take a flying leap.