I tried to take on Decker wearing Leather Armor and packing a dinky Shotgun, with Ian as my backup with his 10mm pistol. Kane DESTROYED me. Multiple times. That psycho has the HP of two Super Mutants and punches like one. And the other guards are also mean jackasses. Kane could clean Sulik's clock and not even break a sweat.

He was a mean badass motherfucker.
-i killed dogmeat instead of recruiting him.
So I wans't the only one, huh? I did the same thing. I thought Phill wanted the dog dead. So I went there and blasted the dog with my hunting rifle. "Bah, its just a dog." WRONG. Its dogmeat, bitch. Dogmeat teared me appart multiple times. He was like somekind of canine god of war, with two times the AP of a normal human and a bite that could bend metal armor.
And there's another mistake in Junktown: I wans't a good english reader yet, so I thought Killian sent me to kill Gizmo instead of getting proof of his activities using the tape or the bug. So I just waltzed there like some kind of Wasteland Vigilante straight out of the Hard-Boilled Anti-Hero school, insulted the big man - hell,
outright called him a fat mobster fuck - and then I shot him in the face while Ian skullfucked his mute bodyguard. Then I shot my way out of Gizmo's sleazy cassino. I killed all the guards and all the patrons, like somekind of heroic psychopath. Then I went to Killian, preparing myself for the moment when I would be showered with glory, whores, money and free guns. Guess what? Lars, Killian, everyone, told me I did Junktown a favor by wiping the fat fuck's operations out of the map, but I did it without proof, which means its better for me to fuck off Junktown and never return. This marked my Fallout experience forever.