'What is a cynic? A man who knows the price of everything and the value of nothing.'  The following might be heard at coffee time in a staff room near you: 'Don't you just hate politicians? They don't do an honest day's work. All they do is invent ridiculous policies that make life harder for us toiling at the coalface, trying to do a good job. Meanwhile, the opposition chuck mud around hoping some of it will stick.' Alternatively, perhaps: 'Give me a cynic any time; they're the ones who know what's what!'
Now, I know you won't believe me, but I think that politicians do a difficult task to the best of their ability. They suffer from the same failings as us, and like us, they struggle on in the hope of making the world better. But I have fallen into my own trap. I have suggested you won't believe me, ascribing to you the cynical viewpoint that you doubt my sincerity.
Effects of cynicism
Some might suggest that the cynic is good for team spirit, uniting us as we lambast someone or the powers that be. However, the Bible teaches that this is not true: 'A perverse man stirs up dissension'  and 'Drive out the mocker, and out goes strife'.  Others feel the cynic knows what he is talking about, although the Bible teaches otherwise: 'The mocker seeks wisdom and finds none'.  Further, 'A man who lacks judgment derides his neighbour'.  What is the result of having a cynic on our team? We might fear being a target of our cynic's attacks. Worse, others may think that we are cynical, and that we will be cynical about them behind their backs.
The cynical clinician
The cynical team member is not as dangerous as the clinician who is cynical about a patient. This is dangerous on many fronts. First, the cynical clinician may not deal sympathetically with the patient. Secondly, his attitude might bias ours, causing us to treat the patient less well than we ought. Thirdly, we might miss the signals our colleague is sending out, and of which he may be unaware. If our colleague displays this attitude towards a patient, we should ask questions like: why did he find this patient a struggle? What difficulties might he be experiencing? Are there any learning points to be addressed? Unless we take this approach, we might miss an opportunity to support him.
How cynicism affects patients
There is a more subtle form of cynicism, and here I sometimes fail. It is the gasp I might make on seeing a certain name on my list: 'Oh no, not her again!' This should not be the voice of a representative of the Lord Jesus.  Patients who produce such a response are colloquially known as 'heartsinks', and may account for 11% of GP consultations.  To my mind, it is not the patient, but the predominantly cynical attitude of the doctor to the patient that is the problem.
This attitude results in twin risks: to one's self in making the consultation less enjoyable, contributing to personal stress or fatigue, and to the patient who is not effectively cared for. Such an attitude may be modified by seeing things from the patient's perspective. One paper states: 'general practice should reassert its acceptance of suffering, whatever its origin and presentation'.  This might require large leaps of imagination and empathy with some patients, but it is our challenge, particularly as we are called to be salt and light. 
A Christian response
What should we do when we next hear the seductively acid tones of the cynic? Well to start with, we shouldn't join in: 'Do not answer a fool according to his folly, or you will be like him yourself'.  Further, Jesus teaches 'Do not judge, or you too will be judged'.  If we do speak, we should ask God to help us to be careful what we say: 'Set a guard over my mouth, O Lord; keep watch over the door of my lips'.  If we confront the cynic, we should remember that a mocker resents correction.  Better still, we shouldn't listen in the first place, if that's possible: 'A wicked man listens to evil lips'.  More positively, we should remain cheerful, remembering 'A cheerful heart is good medicine'.  If we have a team member who hasn't a good word to say about anyone, we could lead by example, praising others where appropriate.
Does this mean we should believe all we hear? Certainly not! Jesus sent out his disciples to 'be as shrewd as snakes and as innocent as doves'.  Paul said: 'Test everything. Hold on to the good.'  Although he was referring to prophecies, I think this concept can be applied here too.
Cynicism hasn't made it onto the list of the seven deadly sins described by Pope Gregory the Great.  But I hope I have shown that its malign influence should not be underestimated.