Ignore them, mostly. I have a girl in my training class at work right now that is just THE most negative nancy I have ever met in my life. We are a call center that serves military members and the first week of training we had to watch all these cheesy military propaganda videos and I knew that they were cheesy and I don't agree with the conflicts our country is involved in right now but despite that- I STILL appreciate that military members take time away from their families and sacrifice a lot to serve our country. She took this job KNOWING this was going to be her job and she just got so negative talking about how "soldiers don't know sacrifice, little starving kids in Africa know sacrifice. Soldiers choose to do what they do and they can't complain or expect to be treated special." WHY would you take a job that serves the military if you clearly don't respect/value military members?! Then she's late to work everyday because doesn't have a car and her roommate is nice enough to bring her to work but it's always the roommates fault that she's late, always someone elses fault why she doesn't have a car/can't be on time. Just super duper negative. I tried expressing empathy for living in a roommate situation you don't like, empathy for not having a car and expressing empathy is the worst thing you can do because they take it and run with it and see you as someone who will listen and they dump even more of their shit on you. Just ignore them and resolutely do whatever you were doing before they started being negative and eventually they'll get the message that no one gives a fuck about their excuses or perceived problems and STFU about them.