Both of my big ones have already been mentioned.
Growls for vocals:
Used to immediately discount music with growls as complete shit. When sampling a new band’s material, as soon as I heard screaming, they were dead to me. Then, for some reason, I really started enjoying Into Eternity’s music, and Buried In Oblivion specifically was my gateway drug into the growling world. I was soon tolerating and eventually enjoying growls in music, especially bands that altered between clean singing and growling. It opened doors to In Flames, Soilwork, Opeth, Scar Symmetry, and several others. I was glad I was wrong initially.
Devin Townsend:
Boy did this start off on the wrong foot. My first taste of Devin was from the Working Man tribute album to Rush. Absolutely *hated* his rendition of Natural Science (my absolute favorite Rush song, so the damage was magnified), especially how he butchered the vocals. Swore him off completely at that point. Two things re-ignited my curiosity. The first was I somehow found SYL’s video for “Relentless” and watched. I remember thinking something along the lines of that was fucking intense, and that was fucking awesome. So I started checking some stuff out, and bought at different points Accelerated Evolution, Terria, and Ocean Machine. While the music was fine, nothing clicked at all and I just figured he wasn’t for me. And then some years later, by happenstance, I found his short YouTube video of him laying down guitars for Resolve! from his Addicted album. The prechorus and chorus riffs, plus the awesome vocals by Anneke, plus his absolute energy while playing sucked me in and was impossible to not watch with some excitement. I bought Addicted shortly after release, loved it, and have been a fan since. I don’t love all his stuff since then, but when he’s on, boy can he hit my musical G-spot...