If I had a worst enemy they'd have to do me in the worst way imaginable, absolutely unspeakable things for me to even consider wasting energy on them. And when I do oh gods above have mercy because I will HATE.
I would dedicate my entire life to becoming as successful as humanly possibly SOLELY to have more resources to ruin theirs. I would recreate the big bang and destroy EVERYTHING if it meant I could ruin their happiness even for a short while. I would create actual immortality and force it upon them as well as me just so I could torment them for eternity.
There is no way to describe the amount of HATE I would feel and exhibit because even describing it would feel limiting
I would break my morals over and over again just to see them cry or break mentally and even then that still wouldn't be enough.
I would not let them rest for a second without the fear that I am coming for them. They will be unable to form bonds and relationships or find comfort in anything because they know I will be there to ruin it for them.
I would LIVE to see them SUFFER
People wouldn't even be able to ship us because the hatred I would exhibit would be too powerful to be mistaken or compared to love
I would spend every waking moment wishing the worst upon them and then doing everything in my power to bring those wishes to life
The Reverse Flash, Black Manta, and Lex Luthor would bow down and quiver at the mention of my name just from the amount of hate in my aura alone
so yeah you wouldn't wish that upon your worst enemy but I definitely would and more