I'm trying to quote someone's tweet and planning to use the ellipsis as a pause in my sentence (due to showing an aggressive attitude)
You... SNOB! Stop gossiping about me!
I think that it is better you simply say 'You SNOB! Stop gossiping about me!' because the ellipsis causes it to sound like you are hesitating and can't think up a good insult. However, the ellipsis is certainly not grammatically incorrect, so posting like that is perfectly fine; it is simply that you don't sound aggressive like that.