As for visual novels, the biggest reason is definitely the characters. Of course, having a character whose design I love is a huge plus, but one of the best things about visual novels is getting to know the characters through their conversations and interactions, and discovering sides of them that I never expected. I especially love characters who seem sweet and gentle at first, only to reveal a much more possessive side once you get deeper into their route. If there's a character like that, I'd definitely want to play the game and see how that side of them gradually unfolds.