What annoys you most in responses to apartment/housing listings?

I’m currently trying to find an apartment share for my move-in date in May, which is a long time from now judging from most of the listings that I have seen, which list now-Feb as the move-in date. For listings I’m interested in that don’t specify a move-in date, I send an email saying I’m looking to move in in May. Does that annoy the other person? Because if they’re listing now, they’re obviously looking for someone to move in now?
What are other things that annoy you in responses?
Is there etiquette?