This is pretty corny, but one time I'll never forget I saw this guy at a pharmacy or something when I was fifteen and he had a really confident attitude, like he just didn't worry too much about anything. He was about 6'0 or so and ripped. Not bodybuilder level but athletic, like he could throw some weight around.
Anyways, he was wearing a t-shirt and it said "Yeah... I work out."
It was a perfect match for his demeanor.
The Slayer shirt is a nice conversation starter for both legit, quasi, and pseudo metalheads. Taxi driver was an awesome movie, but anybody i see with a t-shirt of that it's already on the wrong foot, I would avoid you, personally. It's kinda weird, because he was a psychopath.
I think for t-shirts it's solid to wear stuff you're associated with. For example, I was in the US Navy, so i'll wear Navy gear sometimes. My uncle went to a couple ivy league schools so I'll wear some of that and get approached b/c of that. I'll wear shirts of local bands that I've seen and know. Fav. sports teams. Institutions I'm involved with or like, brands I want to promote.
Whenever I see a guy with a fresh t-shirt with some big brand, or movie reference, or crazy design I think, 'Wow he actually went out of his way to shop and buy that,' especially if it's out of left field. The perception --to use the taxi driver reference-- is 'alright, he must really like Robert de Niro's character in Taxi Driver. Robert de Niro's character was violent and crazy.' If that's what you want to co-sign, then ok. It's hit or miss I think because maybe t-shirts aren't the best platform for high fashion statements. For me, a go-to is a generic white tee. The cheaper, the better.
Harlem white tee.