Never eaten brain from a mammal, not sure why, but there is a blockage there. But fish head/brain was nice. (maybe because the animal is smaller, or maybe because it's not a mammal? not sure)
But I believe you can train your self. Eating raw eggs was unthinkable for me 6 years ago. Raw meat was never a problem, felt very easy and natural. Same with raw fish. I think this has to do with the fact that in my childhood we had sushi once in a while.
Traditional thais thinks dairy is totally disgusting (but it's changing fast).