I guess I'm lucky enough to look like a complete psycho and I have been told that I am intimidating because of my height and build (I am a 6'2 ex Thai boxer ) so not many people ever try it on with me. I have been threatened with knives and guns in my time and the secret is to stay cool and if you can just walk away until you see the chance for retribution. The funniest was a phone call when I was living in Newcastle upon Tyne.
Some guy rang the house I shared with 4 other guys and asked for me, I took the call and some guy said "I'm coming round to blow you away man, you been fuckin' my girl so get ready to die". I thought it was my mate Chris at first and laghed and said "c'mon Chris stop pulling my pud dude ,, I know it's you". Just at that mo Chris came walking in and of course I realised it couldn't be him, I then decided to call the guys bluff and told him "hey man you come round because I have a lovely brand new 45 waiting here to put one straight through your freekin head"", "you wanna see if your shotgun is better than my 45 feel free to come round". Funnily enough the guy never showed but to this day I don't know wether it was a wind up or for real.
Cities are funny places.