A love potion to poison the antisocial with

I love the mind answer, because it is absolutely true that avoiding conflict and being able to de-escalate heated situations are invaluable.

But on a different plane, actual fighting skill for situations that ambush you still has its value. I thought about various weapons, and some are impressive, but unfortunately, very few of us could say we would be able to be armed with these wherever we go. But mastery is not much use where you aren't able to actually have it with you. So with that in mind, I would love to have "unrivalled" mastery over my own body as a weapon. Imagine 10th degree blackbelts simultaneously in Karate, Kung Fu, Judo, Taekwando, Aikido, and Judo. I am reminded of that old tv show western fantasy, "Kung Fu," with Kwai Cheng Kane, the "man of peace, who fights like ten tigers." I loved that silly show.

We do short swords, often 2 of them, sword and dagger, sword and buckler.
Overall the longsword wins in a mixed duel. Our club went interstate 2 months back against a rapier specific club who was hosting the event. Even in the rapier events, every one of our members beat everyone of theirs using an old German style.
I agree with @JimG re the mind, that is how we conquered the planet. But as they say, never take a knife to a gunfight.
Someone will always have an advantage no matter what weapon you choose.

Persuasion.

As a veteran with 11 years of experience in the army, I qualified expert with at least a dozen weapons, and trained in hand-to-hand/ unarmed combat. The most dangerous weapon you can master is your mind.

My rifle/pistol/knife/hands are merely tools. Without the knowledge, skill, and will to use those tools they are useless. Actually they are worse than useless, in inexperienced or hesitant hands, they are dangerous to their user.

Make your mind your primary weapon. Study Sun-Tzu and focus on winning battles without fighting. I am skilled in the use of weapons that you may not even recognize as weapons, but if I have to resort to using any of them, I've already failed.

If I could lift it-and I was a lot taller, lol-the Claymore is kind of awesome.

Throwing knives. As kids, my brother and I played throwing knives for hours. We made our own from what we could pilfer from our mother's knife drawer. Some of the games involved circles drawn in the sand, some targets we drew on trees, some involved throwing knives between our own fingers. I don't remember ever getting hurt. We were pretty good! I still carry at least one sharp knife in my purse or pocket.

nukes ?

My limbs.