Yes, these complaints are petty, but here they are nonetheless:
1. Please don't address me as "Mrs." in your cover letter.
"Mrs." refers to a married woman (and even then, plenty of them don't use it). I am not married. And if I were, I would be unnerved that you somehow knew that. Either way, I wonder why you're assuming it.
The term you're looking for is "Ms." It's the female equivalent of "Mr." -- in other words, it makes marital status irrelevant.
I'm not rejecting anyone over this, just noting that it's mildly weird. Also weird is that the people most likely to do this are male recent grads.
(For more on this topic, this post over at Clue Wagon has lots of input on this in the comments.)
2. It's not a great idea to apply for a job with me and then add me to the email list you use for mass-circulation of announcements promoting your band, your fundraiser, your side business, your inspirational story, and/or the news article you found interesting this morning. If you do this, it will annoy me and make me wonder why you thought this was appropriate.
If your email program is automatically adding everyone you've ever emailed to your "contacts" list, either change your settings or -- even better -- never send a mass email to your full contacts list.
I told you they were petty.