Around the time that the 2010s My Little Pony was getting super popular, my manager was really annoyed by it because his kid LOVED it and he had to watch it and be exposed to it constantly. He didn't mind that his kid liked it, but just like one of those songs that gets played waaaaay too much on the radio, he was just super sick of MLP at this point.
He had a little shelf on his desk with a bunch of little figurines for various nerdy things that most of us on his team were also fans of - Batman characters, horror movie characters, etc.
One day while in Walmart, I passed by an end cap display that had bins full of blind bag, tiny MLP figures for a dollar each. I immediately bought 5.
I slowly started adding them amidst his figurines on his shelf, about one per week. It took until after I placed the third one before he finally noticed and immediately came storming over with them in hand, stopped near my desk....and then turned to my coworker and just went, "Dammit Gary!!!"
A few months later for Valentine's Day I saw a bunch of small MLP valentines cards that were all connected accordion style, so I bought them and then taped them along the edge of his desk like a little table skirt. That time he knew it was me, obviously.