Who is Chopper? Well, he's a character played by Ronnie Johns from Australia and those are words to live by.
This Chopper t-shirt comes courtesy of Sweat-Shop Productions. Those guys comes up with very interesting images like Benny Hinn Touched Me (Again); Dot Communism and Peace in the Middle East. It's a pity that those weren't sold as t-shirts.
But to contend with the loss, I'll leave you to acquaint yourself with Chopper going about spreading his wisdom.
edit: I'm such an idiot. I was told that Ronnie Johns played a real life character called Mark Brandon "Chopper" Reed. That t-shirt is of the actual character, not Johns.