I don't know what it is about the last few weeks - maybe the change of season; maybe something in the water - but I've been absolutely amazed at how often people have showed a complete lack of comprehension for who was in the room with them. 

This may sound more calculating than I intend it to, but I think its a good practice to always consider who you're talking to before you start in on a conversation.  This is especially true when you're negotiating for something, making a request or otherwise trying to drive to a specific outcome.  I've witnessed several pretty amazing examples of a complete lack of thoughtfulness around this notion of late.  From making idle (and counter-productive) threats, to inappropriate requests, to outright lying (which was sure to be uncovered). 

Stop and think...then talk.