What if you, one day, bite into an apple that has a worm in? You'll probably feel different about apples after that and you calibration data is now useless.
As I said, just consider the sparse information you get out of an EEG or FMRI and compare it to the vast information that make up your thoughts, memories, feelings etc. It's simple mathematics, it won't work unless you find a way to extract much more data non-invasively. Upon that, you most likely won't get away with a single calibration.
Yes there are awesome results, like controlling a cursor or artificial limbs with your brain. But that only works because your brain learns how to control it - not the other way around.
Continuing that thought, I can imagine a system where the user can learn how to express certain emotions to a computer - but that still leaves open the question of how to induce them into another user, which is a completely different task that we even haven't touched yet at all.