I am guilty of a couple of these.  Sometimes I click on a link, read the article later and then send out the link - I can't retweet it because I don't remember who originally posted it.  And I try to acknowledge everything that is said to me or retweeted for me but occasionally I can't keep up.  The article I posted on Monday got retweeted a lot and after a point all of the thank you's became too much.  But, like you, I get a little annoyed when I comment or talk to someone and they don't reply ...

And I have some soccer twitter friends and I'm sure we can be annoying on the weekends when we are watching matches together through twitter.

I completely agree about the swearing.  I swear a lot in real life but I don't want to read it in my stream either.

And I would have to add auto-dms.  They are one my most hated things about Twitter.