It took me a long time, my stepmother use to force food on me as I was leaving after having come over for dinner and I'd do the "No, I don't want it, need it, etc." and she'd keep trying :-) My husband though would just "take it". Then, he explained you can do whatever you want with it; it's a gift and "yours" so you can eat it, throw it at the wall, trash it, whatever! I finally get it and now I'm big on not doing leftovers, I just throw them away. Might be wasteful but it's "paid for", it just costs a bit more. Don't think about it, just take it and then trash it. If family asks how you liked it, just say something nonsensical like, "I liked it fine!" and smile broadly. If you can't trash it right away, give it away. Give it to a friend you know understands to deal with (I've given things I couldn't throw away to my therapist) or a family with kids, etc.

I would have taken it, opened the lid if it was in a carrier, and then "tripped" and accidentally dropped it on the lawn or street on the way to the car :-) But I would have tried not to keep it long enough to "worry" me so I was constantly thinking of/obsessed by it.