You may laugh at strange English on T-shirts that some Japanese wear.
On the other hand, Japanese people may also laugh at Kanji tattoos on some foreigners’ bodies. I read a funny story about Kanji tattoos, though I don’t know if the story is true or not.
“Free” has some meanings like “freedom”, “for free”, “smoke free” and so on. A guy wanted to get a tattoo with the word “freedom” in Kanji. But maybe there was a misunderstanding between the tattoo artist and him. “Freedom” is “自由” in Kanji , but what he got on his body was “無料” which means “free of charge” or “for free”.
In terms of strange English printed T-shirts, you can take it off. But once you get a tattoo, it is difficult for you to get rid of it. So be careful, if you get a Kanji tattoo.
Kanji is originally from China. So there are some similar characters in Kanji and Chinese but pronunciations are totally different in general. A funny thing is that “手紙” means “letter” in Japanese but “手纸” means “toilet paper” in Chinese. (The characters are slightly different.)
Without Kanji, native Japanese speakers can’t read Japanese quickly. According to an article I read, when native Japanese speakers read sentences in hiragana and kanji and when they read sentence in hiragana alone, their brains move differently.
Japanese learners may find leaning Kanji to be difficult. But don’t worry. I’m not good at Kanji too, even though I’m a native Japanese.