There are three things that gets to my bias list. In order, it would be a the personality that is displayed, a great voice, and a smile you can’t forget. 

Personality is actually pretty hard to measure. The only time you see this is through variety shows. SNSD’s Tiffany personality hooked me through Hello Baby. Her behind the scenes motherly care had me in awe. I started to pay more attention to her and how humble she was. ^^ Nichkhun from 2PM swept me off my feet because of We Got Married. I’m pretty sure I don’t need to explain this if you’ve seen the series, haha. BEAST’s Yoseob’s charms from all of his variety shows made me think he was just a funny guy, but his fanboying from IU’s cover of Queen hooked me, lol.

Voice. Voices are a big deal for me for some reason. I love all types of music and voices can change everything. A Pink’s Eunji husky yet powerful voice melts me. I just stumbled upon Ailee and she’s a mature, independent voice compare to IU’s sister cuteness, lol. Then the intensity of emotion that 2AM’s Changmin has when he sings, Even If I Die, I Can’t Let You Go has almost made me cry. The emotion that can be given through a voice definitely plays a part in my biases. Check out Taeyeon’s emotion during her performance in Japan of I Love You from the Athena OST.

Then a smile. A memory of smile can linger after seeing a genuine one. Tiffany’s smile definitely leaves an impression, even cool, calm, collected Oniontaker couldn’t stand Tiffany’s lingering smile, lol. Siwon from SuJu has this memorable smile because he’s just so silly. His reactions Running Man and Shibrows are just his charm. Then, miss A’s Suzy has a innocent, cute smile, that can calm you down, you know what I mean? lol.

Thanks for the question! I love these types because they allow me to actually answer questions that I’ve asked myself before.