You know "Engrish"? The incorrect and strange English that appears throughout Japan is something some English (and even Japanese) speakers enjoy laughing at. You see funny English on signs, company slogans, and, most often, t-shirts. Hahaha, right?
But what about when foreigners don t-shirts with goofy Japanese? More hahaha.
Japanese and English are very different. That's why, as Kotaku previously pointed out, Japanese video games are changed when they are localized into English.
Yet, there are similarities in both the Japanese-speaking world and the English-one. People in Japan think English looks cool, which is why it appears throughout the country, whether that be on signs or t-shirts.
Likewise, many Westerns think Japanese looks cool—hence foreigners getting Japanese words tattooed on their bodies.
Some of the wearers probably have no clue what the shirts say. And some definitely know.
Why are some of these Japanese shirts strange? You just don't usually see these sort of things written on shirts in Japanese—in fact, you rarely see shirts with Japanese written on them in Japan. English seems to be preferred.
And bad as these shirts get, they're nowhere near as awful as some of the incorrect Japanese tattoos. You can always take a stupid shirt off. A tattoo? You need lasers.
どうぞ or "Please"
毎日が地獄です or "Everyday Is Hell"
やわらか冷凍 or "Gentle Freeze"
道をあけろ！ or "Get Out Of My Way"
痴漢注意 or "Beware Of Gropers" (And yes, that's Ron Jeremy in the background)
痔 or "Hemorrhoid"
変態 or "Pervert"
藍染 or "Indigo Dye"
私は日本人です or "I'm Japanese"
巨根 or literally "Giant Root"—slang for "Big Dick"
ゆったりパンツvsぴったりパンツ or "Loose Underpants vs Tight Underpants"
ヌーディー or "Nudie"
オタク or "Otaku"
糞 or "Poop"
自己嫌悪 or "Self-Loathing"
私は、バカなアメリカ人です or "I'm A Stupid American"
タークのようにして or "Act Like You Are Talking"
私変態 or "I'm A Pervert"
結活 or "Looking For A Wife"
この野郎支払え or "Hey Asshole, Pay Up"
I... I... I really don't know what to say.