|There are many threads on here explaining the way people have decided to vote.
There are no strict guidelines. And there are countless different approaches to voting.
The best rule of thumb, I think, is to regard each photo the same way you'd like your own photos to be considered.
For example, nobody likes receiving 1's - would you want your own photo to score a 1 just because it doesn't make sense to the viewer? And remember, there are many different people here with vastly different geographical and cultural backgrounds: it's easy for someone not to understand another photographer's point of view.
Also, I'm of the opinion that no-one deserves a 1 just because you're "irritated"... If the photo really does bother you that much, rather just give it a reasonable score, and then burn that photographer's village ;-)