I've made this comment on here before, but after being out for seven or eight years I found myself in Spain with some coworkers having a business dinner. My boss wanted to order blood sausage and I felt my heart sink. It was as if I was a JW all over again trying to elegantly weasel my way out of an awkward situation while attempting to minimize the social impact of being, frankly, weird.
Blood is one of the taboos I've yet to break. I just have no desire to eat food made with blood. It doesn't sound appetizing to me and I tend to faint when I have my blood taken, so I've not donated blood either.
But it was a very eerie programmed reaction, even after all those years. I've read scientific articles describing how neural connections are formed in the brain that cause you to react instinctively to certain scenarios, a learned response. There was no reason for me to have the reaction I did other than the fact that I created those connections in my brain all those years ago and simply hadn't exerted the effort to re-train myself how to respond in those situations. On a conscious level, I no longer believe there's anything improper about eating blood.
Even today, I occasionally feel pangs of guilt after a night of heavy drinking. I'm not sure we're ever able to completely shake it off.