Anime is a welcome change from the American cartoons we have all become so accustomed to. The art, even if unrealistic (not more irrealistic than most other cartoons though) somehow still has an appeal and allows a lot of personality to be expressed/put in the characters through liberties allows and style it has. In general the plot is also better and the characters are more believable. It is geared towards an older audience, and therefore many young people who have given up on American cartoons for entertainment (though a few shows like the Simpsons do not suffer the massive loss of viewers beyond a certain age) when they get into contact with anime. Some of it does require an acquired taste, but that goes for almost anything in life... A lot of the things we appreciate as funny or enjoyable in shows like Friends or romantic comedies like Notting Hill are after all also things we learned to appreciate and enjoy by watching similar humor. Anime is no different.
Ofcourse, that doesn't take away that it is just a cartoon and eventually adults tend to prefer seeing life actors rather than drawn ones. Still anime in general is of pretty good quality and it should come as no surprise that non-Japanese viewers can appreciate it as well. And the fact that it is in another language also makes it something new and fresh, something unexpected. And this ofcourse results in a sub-culture/community which you can 'belong' to. Which is again a positive factor in getting people interested in it.
I could prolly ramble on more and try to make some points, but I think I won't. Fact is, cartoons are taken a lot more seriously in Japan and are not just for 12 years and below. A lot more effort is put into them and they are tuned to be appreciated by more adult people.This is probably why they are appreciated.
Valtiel, you should make a clear distinction between anime and hentai though. They are two quite different things.
A couple of my favorite animes in no particular order:
Initial D
Fullmetal Alchemist
Saber Marionette J
Naruto (I am a naruto-baka!)
Gundam Wing/Seed/08th MS Team
PS. Naruto fans are also known as NaruTARDS. 8) 8) 8)
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