I first saw folks posting pony memes back in 2011-2012. I thought it was ridiculous, but the more folks talked the show up, the more my curiosity was piqued. Still, it wasn't until I heard John De Lancie was in it (and that he was playing an expy of Q, one of my favorite characters from Star Trek: The Next Generation [which is itself one of my favorite shows]) that I decided to give it a shot.
I came in during Season 2. The first episode I watched was "May the Best Pet Win," and I thought it was... eh, okay. Not as cringe-worthy as I was expecting, but nothing to write home about. So then I said, "Okay, this show is at least tolerable. Let's find this episode with De Lancie." So I did... and I was
blown away by how good it actually was.
Funny, entertaining, and with just enough adult-aimed reference jokes to appeal to my geeky side (like the Star Wars homage at the end), I finally said "This show might actually be worth a shot."
I finished out the season and the rest, well, is history.
I like a ton of characters. I can't think of many that I actually dislike. But, let's see...
-Discord, obviously, as he's what drew me into the show
-Rainbow Dash, despite sometimes being an idiot and a pain in the butt, is still one of my favorites
-Pinkie, because I enjoy jokester characters
-Twilight for being a protagonist who is actively studious and intelligent
-I also have a soft spot for the CMCs, Scootaloo in particular
I could go on, but I think that ought to answer the question. Thanks for asking!