1) Buy something he/she absolutely hates.
2) Let he/she talk you into donating it to Goodwill.
3) Visit Goodwill later that week, spot that item on a shelf, and when your partner's back is turned, place it in your cart.
4) When he/she looks in the cart and asks, "What is THAT?," pretend you have never seen this item before your trip to this Goodwill.
5) Innocently say something along the lines of, "Isn't this fabulous? This would look SO good on our dining room table."
6) When he/she freaks out, raging, "We had that! That is the EXACT fruit bowl that on our dining room table. THAT EXACT SAME ONE! And then we donated it! TO THIS GOODWILL! It's the SAME ONE!," feign confusion.
7) Persist, "I don't think so. You must have it mixed up with a different fruit bowl. The old one was tacky. This one is great. I think it'd look perfect in our dining room."
8) Keep up the good work until you've achieved your desired goal.
(PostScript: I love my husband. We are not divorced. Even though we probably should be, since he has pissed on our kittens, tried to make me live on a merit-based allowance, and once convinced all of our neighbors that he is a pedophile. But he's a good guy overall. He just happens to disagree with my opinion that the fruit bowl would look great on our dining room table... again.)
True story: Life would be super swell if we all embraced our OMG side instead of living a Facebook-friendly existence. So, let it out. What have you purchased that your partner HATED? Did you place in a position of prominence so your partner would HAVE to look at it? Or is that just something I do? How great is Goodwill, though, amirite? Also, did you know that all of the Goodwills have collectively collaborated on an eBay-esque bidding site called www.shopgoodwill.com? It's amazing, y'all. I spend hours (and lots and lots of dollars) on there, finding stuff that my husband is going to hate, because, well, one day I'm going to need the plan I listed above. Feel free to disclose details. You're safe here.