I used to dislike the "this is why I love Hacker News" comment. It's not so prevalent anymore, but it was very common 3 or 4 years ago.

And while we're on the subject, I dislike the use of the word sure on nerd sites. I say nerd sites because I haven't seen it (ab)used so much on other sites or movies.

Basically, people say "I'm sure" to mean "I think" and "I'm pretty sure" to mean "I kind of think."

I just went to reddit and the fist thread on my front page had 3 instances of "pretty sure." I'm pretty sure it's the most common phrase and it gets posted thousands of times per day in contexts where the user is not sure at all.