Someone you connect with at work (ie send same-time messages all day, take bathroom breaks together and share your lunch). The way in which you interact at work leads people to believe you are best friends when in reality you would never been seen outside work with them.
Steve: So are you inviting Tonya to the Pub Crawl?
Jessica: No bro, she's a total work friend.
a quickly formed (nearly instant) adoration for someone of the opposite sex, based purely on a shared interest/obsession. Be it a sports team, band, tv show or hobby. Often confused with a crush at first but this intense feeling fades as you get to know more about the other person
Steve: Mike has been talking about that girl Beth ever since he found out she loves football as much as he does
Jessica: That fan crush will be over as soon as he finds out she hates his favorite team!