Ok, this will probably sound petty to everyone, but here's my story...
My mum re-married about 10 years ago and the guy she married has a daughter. My younger step-sister was/is one of the most arrogant, self-centred, nasty little pieces of work you'd ever meet (I say was as she moved out of my mum's place a year ago giving very little in the way of contact other than to be nasty or to ask a favour/for money, has since got in contact again and seems to be a lot nicer nowadays). She would constantly berate my side of the family, state out to us that she wanted nothing to do with us and went on and on about how she hated us all, including her dad. Basically put, she's always been utterly spoilt by her parents. The problem with her, and her father to an extent, is that they will act horrible around us and their friends, but in front of strangers or my grandparents and less close family, they act like little angels.
Now, not to blow my own horn, but I was raised to be nice even when I don't want to be. Whenever I received a gift, no matter what, I always smile and say thanks (and my parents hate me for it, simply because they never know if I actually liked the presents I got, thus making it terribly difficult to shop for me

).
So, several years back, my mum paid for us all to go out on a big month long holiday. First to Hong Kong for a couple of days stop-over, then to New Zealand to see our cousins and her dad for 3 weeks (over the Christmas/New Year period), and then a week out to Florida. Sounds lovely, right? Sounds like something to be very thankful and kind to us for, right? Not to my step-sister. As usual, she was a horrible ***** towards us, but as soon as we were around our family, she was as lovely as peach pie.
This was the first year that I caught Bronchitis (and have had it annually ever since). I couldn't sleep, I could barely breathe, etc. I needed to lean up to sleep, but I had the joy of sharing a room with her so she decided I would have to have the flat, solid bed that would force me to lay down at night. I would cough and wheeze most of the night, and thus she would constantly throw stuff at me and shout at me so SHE could get to sleep.
While I was bed-ridden, my aunt (whom I'd always been on great terms with) came in and started telling me how much of an angel my step-sister was and I snapped at her for it... so I was then eternally glared at and spitefully hated for the rest of the trip by my aunt.
To top it off, just as I was finding myself well enough to get up and wander around once more, I came out of the room to find my step-sister sitting there crying on the sofa (no-one else was in the house at the time). So I sat there, still coughing, while listening to her little sob story. All I wanted in return afterwards was just one hug, just to try and cheer her up... she refused and her reason? "Because you smell...", at which point the tears just magically dried up and she walked away as if nothing was wrong.
Ok, so my point of telling you all that was to explain WHY this was such a bad present.
The present she got me that year, after all I'd been through in that fortnight alone, was a small, cheap (and I only bring up cheap because it looked like it had been bought from a thrift store... a 99p shop), book titled "The World's Best Brother".
I flipped out... in front of my whole family, both close relatives and family from NZ. I went mental at the idea that after all she'd put me through since I'd met her and her dad. It was a total f***ing insult. She'd done it just to make herself look wonderful in front of MY family and I was having none of it.
So yea. That's the story of the only time I've ever openly rejected and hated a present.