M.L.
Is it: "I must not be a very acceptable person if I can't make others happy with my gifts?" Or is it: "These people don't appreciate what I do for them"? Both lines of thought are able to tie you up in knots, but they're not the same.
If it's the second, please realize that no person on earth is appreciated to the extent that that person thinks he/she *should* be! And there are always, unhappily, a few people who can't be pleased no matter what you do. It might be better not to expect any appreciation or thanks at all than to require it.
If it's the first, please think about this: your value as a human being is not determined by the gifts you choose for people. Your job as a gift-giver is merely to do your best with the information (and money) you have to find something the person *might* enjoy or benefit from. But your world doesn't turn on what you decide. It won't end if your gift is snubbed - and it won't really be much better if your gift is liked; that feeling will last only until the next gift-giving occasion pops up.
The fact that your parents don't use the gifts they receive indicates a number of things to my mind, but criticism of you personally isn't one of them. If they are critical people - in general - all the time, *they* have a problem, but you don't have to be the same way. You can start by not being as critical of yourself as you're doing.
I imagine most people who know you rather like you, or at least find no harm in you. And that, however lame it sounds, is a real compliment. You're not a horrible person after all. Don't be obsessed with what people might think of you, or what they might say about you. Don't make Christmas presents the test of your value. Just do the job, enjoy doing it as much as you can, and be done with it. After that, it's out of your hands and you can think, "Well, I did my best. Now I'll go do something else."