As a tentative rephrasing, something that's "emotionally implausible" is something that "I would never do" or that "could never happen to me."

Allow me to rephrase more precisely for you. It's not plausibility that's at issue, it's whether you have a thought that causes you to stop visualizing.

If, as you mentioned in your previous comment, you imagine slapping your mother and "fail utterly", it's not because you can't imagine it, it's because your (early) evaluation of what you imagine causes you to stop before you can really put yourself in the situation.

Knowing that, you can ignore the reaction that tells you it's bad, and proceed. IOW, it's not that you can't imagine slapping your mother, it's that you prefer to stop before you actually experience what it would be like. In other words, it's not "can't", it's won't.