Dear OP,
Suck it up, crybaby. This is clearly a problem with you. Healthcare in general is well known to be full of nice, well-adjusted, benevolent people who work well as a team. The problem is clearly you. [end sarcasm]
Seriously, I think lots of people missed some basic kindergarten skills regarding playing nice in the sandbox. Maybe these people can come hand out T-shirts in some units:
http://www.youtube.com/watch?v=6ZjipbU0Pk4
Hospitals are supposed to be a theraputic environment. Do you think patients feel all warm and fuzzy when they see staff being jerks to each other? Can you really tell me that you can instantly shut off the attitude when switching from interacting with a colleague to interacting with a patient? I call BS, and anyone who is honest in reflecting on their healthcare experience knows that malevolent attitudes spill over onto patients all the time, not a plus for the whole healing process thing.
More seriously, being a jerk is dangerous. Do you think you get a more efficient report when you smile, say hello, and make the person handing off to you comfortable, or when you bark? Which attitude do you think encourages double checking, quick disclosure of errors, and collaborative work to solve problems?
Even more seriously, depression, suicide, drug use etc. are all overly prevalent among healthcare providers. Yes the job is stressful by its nature, but do you really think that everyone trying to prove that "my job is really really hard...you can tell by how irritable I am" and being aloof or outright offensive with one another has nothing to do with these problems?
You don't' have to go around giving foot massages to everyone you meet....but simple (basic - KINDERGARTEN!) human interaction skills like saying and responding to "good morning", smiling when you see other people, not intentionally humiliating people when they make mistakes, and being supportive of new people could go a long way to making hospitals less miserable hellholes. make whatever excuses you want, but if you are not pleasant to be around, YOU are part of the problem. It takes..well...zero extra seconds to smile, 0.2 sec to say "Hi", etc.
Everyone has off days, but in my experience many people in healthcare make it a pattern....and it's time to call it out as a bad thing.
edited to add: in summary, I don't mean to argue: "be civil" or "be professional"....I mean to suggest a more radical idea...try being actually overtly, obviously, conspicuously, gregariously NICE. It's a goal we can all work towards, and I promise, it won't hurt a bit....
Plus a million to WTEngel's post too.