There are two types of reverse posts - the ones where the person is clearly being wronged in some way and wants validation, eg, 'AIBU to insist on wearing my own wedding dress to my sister's wedding and bringing my kids along in their bridesmaids' outfits?' It then turns out, after 100 'No, you cray-cray' responses, that the OP is in fact the pissed-off bride and has been getting earache from her sister.
And then there's the ones where the OP is being utterly outrageous and is surprised to find out that her made-up villain's point of view is actually upheld by popular opinion, eg, 'AIBU to tell my sister that she can't wear bring her kids to my wedding dressed in their bridesmaids outfits from her own wedding even though their dresses are from Baby Vera Wang, and they only got one wear out of them, and no one will really notice because they're the same colour as her, I mean, MY colour scheme? Oh, and would I be unreasonable to ask my sister not to wear her wedding dress too, even though she really wants to and has been dieting for two years to fit into it again?'
cue another 100 'no, you would be absolutely reasonable to tell her not to do that because she is MAD!' posts, followed by a sudden outburst of 'You're all a bunch of bitches and you don't understand' posts.
You can usually spot reverses - there'll be a very long and detailed first post, and then minimal, one-line responses, because the OP has to inhabit the brainspace of someone she clearly loathes or resents. Then, inevitably, reverse posters flip and flounce.
I actually really enjoy a good flouncy reverse