How do you handle negative people?

You arrive at work cheerful after getting up early enough to get in your workout, share a cup of coffee with your husband and deal with a little unexpected traffic before getting to work to be welcomed by the bad attitude of your coworker. What do you do?  Do you lash back, worry that you have offended her in some way, let your own mood go south? This all depends on where you are in your own life.  At the highest point of self maturity you would completely know that this has NOTHING to do with you AND truly try and empathize with what is going on in THEIR life.  Is this out of character for this person?  We all have our own stuff that we're dealing with and usually when we encounter a bad mood, negativity from another person it has nothing to do with us.  Since I've been working daily on my own personal development this gets so much easier to understand. Getting beyond my own ego, insecurity and sometimes paranoia I offer them a smile, some space, a compliment or a direct "is everything ok? you seem really upset.  Do you need someone to listen?" Many times this is enough to actually improve their mood too and offer them a safe, kind heart when something in their life may be upside down. You'd be surprised how much this can help and alleviate yourself from a lot of undo stress and taking on of someone else's stuff.  Even the next time that girl at Dunkin is miserable, offer her the biggest smile, say Thank you and tell them to have a great day.