A riddle about a riddle in Off Topic
Whatever floats your boat! But I mean, the Guru is one of the residents, so if she had blue eyes she'd have left too. At least that's how I interpreted the riddle. And in fact, the riddle could still be solved had she begun with 'I have blue eyes.'
I think the single most useful hint to really understanding the solution is thinking of the riddle in terms of a chain of hypotheticals: 'let's say I have brown eyes, what would the person next to me do on the Nth day?'