I basically bullied bronies in a TF2 server for a couple of months, either trolling them while on the same team or deliberately switching teams to focus them and only them.
I was then humbled by a player who was a brony- I distinctly remember being killed at least 3 times per each of the 9 classes, in which I then raged like the sad little man I was and got banned from the server.
A week later, after I settled down, I went to appeal my ban for a second chance. The ban lift condition was simple- I had to watch the first 2 episodes of MLP, while the admin watched to make sure I was (proof via webcam).
After the first 2 episodes, I understood why people liked MLP, or, at least, why I might myself. I liked the premise of the series premier, and the characters were likable. Most importantly though, it gave my mind a new place to explore via its world building.
MLP pretty much grew on me since then, and I'm genuinely happier for it. Sure, there are cringe moments, either watching certain episodes or certain experiences at conventions, but it's all worth it for all the people I got to meet over the last 5 years.