I love the sentiment behind this shirt so much... Some days you just want to get all Dickensian on someone's ass.
In the classy olden days, people didn't just go around yelling at each other to "F off" or "get bent" or "cram it sideways with a fork." No, when one gentleman wanted to dismiss another in an especially withering fashion, he would tell him, "Good day." And if his conversational partner didn't take the hint or tried to press his point, the phrase would escalate: "I said GOOD DAY" Ouch!
Good Day To You Sir - Glarkware