To be completely honest I got a nose ring because my girlfriend said I'd suit it so I got it, my thoughts behind it were "she's paying, if I don't like it I can just take it out" but honestly it's boosted my confidence a lot - more compliments from strangers and shit. It's nice.
In terms of looking scary, I'm 6'4, strong with a long history of martial arts but I'm the least intimidating person in the world - the tattoos I'm getting only amplify this as I'm getting 2-4 cat tattoos (my cat died last month and I want to immortalise him). My girlfriend has a very cute owl tattoo and my best friend has a cat tattoo too. (Astrocat.) But of course I've met people who try to look scary but most of them already have pretty secure jobs in the music industry (where I live there is one of the biggest alternative scenes in the world) but that's just one city.
My sister's Fiancé is 6'7, bearded, build like a brick wall and has many tattoos and piercings... He's also head chef at a very fancy restaurant. Looks aren't everything when you don't deal with customers. The shock some people have when they send compliments to the chef and this big hurly Viking comes out is quite amusing.