I know it's trivial, but it's like fingernails on a chalkboard when I read these mistakes:
Your/You're - like, "You're driving to the store in your car."
Their/They're/There - like, "They're driving over there in their car."
We're/Wear/Where/Were - as if, "What will I wear, when we're going out?" And, "Where were you going again?
Finally, Am I being too picky to let this bug me?
Last spring I was in an American History class, and we had a large mid-term paper to write. The day our instructor was due to give them back to us, he stormed into the room and chucked the folder on the desk with the words:
"My god how the hell did you people pass high school?!"
He then proceeds to write about the exact same problems you have listed, and rants for another 15 minutes ending with
"How do any of you expect to get a JOB with writing this bad?!"
...I got 195/200 with only 2 typos not related to this issue