Imagine you're walking in the city at night and you turn into some dark alley, and as you look up you suddenly see one of the following three supervillains standing there, real, alive and in the flesh. If you had to pick which villain you'd rather face from the list, which would it be and why:
Not Carnage. Definitely not into some sadistic son of a female cutting my up already. Just kill me, you don't have to repeatedly slash through my juices.
I still have nightmares bout Violator. Nuff said.
I'll go with Joker. As soon as I see him I'll just start laughing hysterically. Then he'll make some joke about how we speak the same language and I'll go home and watch Seinfeld.
Nah. J would have a gun with him, not to mention big, burly, albino guards and Harley Quinn nearby. Harley would kick any poster's ass up and down.
Then, when he catches you, he would spray you with acid just to watch the affect. Or something like stick a bomb in your heart, and threaten to set it off if you don't do what he says. Or something much, much worse.
Joker would not only beat you down, he would torture you for days, or weeks, put you through unimaginable pain, just for laughs. He could also possibly drive you literally insane, after you went through excruciating psychological torture.
At least for Carnage, it would just be a couple quick stabs.
The only thing is that Joker is that kind of sick lunatic that would never forget you escaping and humiliating him because of it. You'd eventually forget about what happened, and then months, maybe even years later, when everything is absolutely perfect in your world you'd get a knock on the door and when you open it it's the Joker wickedly smiling at you.
I have a Batman comic where Joker did that very thing, kidnapping people who years before had laughed at him and booed him off the stage when he was just a normal comedian struggling to do standup. He systematically kidnapped every single one of them (good memory if he can remember their faces and so on) then killed them all.
So out of all of them I'd probably pick Carnage. If there's one way to go it's the quickest way. And who knows, maybe the symbiote might find you a better host and dump Cassidy.