I have a crush on my co-worker’s friend. We’ve been introduced a couple times, but he seemed kind of quiet. Since I already know him, as an acquaintance, how do I start a conversation with him? Your advice is based purely on how to approach someone you don’t know at all.

This is not nearly as tricky as it might seem. I know what you mean about some of the openers assuming no knowledge about the Hot Guy and therefore not being the best choices for someone you’re acquainted with. However, some of the other more “I desperately have a question I need answered” based openers will work just fine. Let me show you:

YOU: Hi! I think we’ve met a couple times—you’re [insert co-worker’s name here]’s friend right?
HIM: Yeah. You’re [insert your name], right?
YOU: Yep, that’s me! Can I ask you a question? I just got off the phone with my girl friend, and we’re utterly perplexed. She went on a date last week with this dude, and it went well. He called today and left her a voicemail that said “Had fun, see you around”. What does that mean, in guy speak? Should she call him back?
HIM: I’d say he’s playing it cool. If he was desperate to see her again, he would have asked her out again. 

YOU: Huh. Do you think she should call him?
HIM: If she wants to—as long as she realizes that it’s possible he’s not that into it. You sound dubious—do you think she should call him?

Now they’ve got a conversation going and it should be relatively easy to segueway into another topic—movies, thoughts on good restaurants (starting with the one the friend went to on her date, perhaps?), travel, etc.

Yours in co-worker crushing,
S