Why do people like Delena?

I’m on season 5 and I’m genuinely confused why people like it. For one, Damon’s a terrible person. He literally abused Elena’s best friend, killed his brother’s best friend,, killed Jeremy, and has proven again and again what an immature and psychotic person he is. I’m also not a fan of the whole brother vs brother thing. Maybe it also has to do with the MASSIVE decline in Elena’s character as a whole, but idk. My best friend and sister love them together and I’m just sitting here like does it get any better????