None of the worst possible hands are my least favorite, just because they're easy decisions. I don't need to be involved in every hand.
Of the playable hands, I used to think JJ like a lot of people. But I've honestly found plenty of success with it, and I'm not afraid to let it go when it looks bad.
Starting to creep up on me as least favorite playable hand is KQo. It's weirdly borderline, and so rarely hits for me. If there's a straight draw, it never arrives. If I have top pair, it seems I'm always up against the A kicker version.
And lastly my least favorite just to see when I peel is any Qx where x is disconnected. Q4, Q3, etc. It just annoys me for some reason.