Blood Thirsty People

Probably, there is no other people like Japanese who are interested in blood type. Many Japanese believe in a relation between a person's blood type and his/her personality, like they believe in horoscope. For example...

"If you have O-type blood, you always express your feeling straight and you have rich facial expression."
"If you have A-type blood, you are introspective, cooperative, and you always take care of the others."
"If you have B-type blood, you are aggressive and do everything without a preconceived idea."
"If you have AB-type blood, you have a rational view and you can make good relationship with everyone else."
"If you are a woman who has AB-type blood, an A-type man makes the best match with you, but an O-type man is worst nightmare..."
"You have a character that is suitable for B-type blood, but mine is not A-type-like..."

People always have such conversations. There were even some companies which employed only persons who had a certain blood-type. (Perhaps, that system must have been abolished.) Psychologist TAKEJI FURUKAWA pointed out the relationship of blood-type and personality on his book published in 1932. Although FURUKAWA's opinion had been forgotten for long, writer MASAHIKO NOMI spread the character judging by blood type with his several books in the 1970s. The NOMI's books based on the theory of FURUKAWA. Now blood-type has been featured in various media.
(Though the most general "ABO classification" is frequently referenced, the other classification like "Rh classification" are seldom mentioned. )

However, the relationship between blood type and personality has not been proved scientifically. The people who affirm the theory always assert that the theory was based on the result of statistics. But, it may be already impossible to get completely fair statistics about blood type in present Japan. Because the belief of the theory is spread too much among the people, the result of investigation will have a bias.

I personally think that our personality must not be related to our blood type. It is foolish that people are going to bring their characters close to suitable for their blood types.
Are you cooperative? Are you aggressive? Do you have rich facial expression?
How can we judge such matters about ourselves? Or are these matters should be judged by others? And should they be called "personality"?
I don't feel like concluding my or others' character too easily. That is probably because I have A-type blood and am introspective...