Things that piss me off in applications:
Saying you have impeccable English. And then miss-spelling a lot of words. Of particular note were the two people who informed me their "Martial Status: Single" - what, you only fight alone? You're some sort of ninja perhaps? Also "I like to lean". That's very nice for you but I'm not sure it's appropriate for the post we have vacant.
Intimate information. Well done to your partner for getting a new job but I'm not entirely sure what the relevance is. Oh so you're married and your wife hasn't changed her surname and you don't have any children? Am I suppose to congratulate you on your support for feminism?
Clichés. "I'm flexible, and like to work hard and play hard, but I strive for a work/life balance". If you use clichés it tells me nothing other than the fact that you like clichés. This does not make me admire you.
Photographs. Please, please do not send me a photograph with your application. Especially if it is soft focus and cheesy. This scares me.
Document titles. Right, so it's not really a surprise that you're applying for other jobs. But saving your document as "Application 90" does not inspire me with hope that you are an amazing person. You are perhaps very determined and meticulous but still, "Application" would be preferred.
Applying for the wrong thing. If you're going to include the job title in your cover letter and say how interesting the research sounds, make sure you put in the corresponding title. Not the title for another job you're applying for. No really, I will notice. Also, if the job advert says "Applicants are expected to have a PhD in a related area", this does not mean we are offering you a PhD. I know it says PhD, but you have to read the other words too.