These days I see a lot of silly people, who believe blood type influences on the person's character.
It's based on a book by a Japanese many years ago. There's no scientific proof for such a conclusion but just a statistics of some Japanese ppl.
I can find a number of sites of blogs about blood type & temper where they say like this.
People of blood type A are
introvert, sensitive, timid, good-looking, boring spouses, not active and bold
they always think of others,
When someone gets angry or upset, they feel sorry even if it's not their fault.
People of blood type B are
active, adventurous, creative, energ