The reciprocity principleA helpful way of understanding what happens in conversations is the reciprocity principle which means something like: people are inclined to give back what they receive. When people feel they are approached negatively the chance will increase that they will respond negatively. The opposite is also the case: when you approach people positively, the chance will increase they will respond positively. A consequence of the reciprocity principle is that negativity in conversations can easily create escalations. A negative remark leads to a negative response. This negative response, in turn, elicits a negative response, and so on.
Once we realize this we can prepare for these kinds of effects. The best way I can think of to deal effectively with them can be seen as a form of unilateral disarmament. It comes down to a strategy consisting of two components. The first component is to reduce your own negativity towards others and to communicate more positively. The second component is to be resistant to the negativity of others and to be able to transform it into positivity.
The first component: communicating more positivelyWith positive communication I do not mean to convulsively ban any negative words from your conversations. Negative words can be very useful and even essential. I mean something more specific. What I mean is to communicate in a way which other people will not easily interpret as an personal attack.
That we we often have negative thoughts about other people's behavior is normal (see the negativity bias) and does not have to be a problem. It may however become a problem when we directly share these negative thoughts with them. When we want to talk to other people about what annoys us about their behavior, we'd better think carefully about how to communicate in such a way that they other person will not feel attacked.
This does not mean that we should shut up about what is bothering us and just be nice and talk about something else. What I advocate is to transform your negative thoughts into specific positive questions and statements while staying on topic. I call this finding the plus behind your own minus. Briefly, this comes down to: if behavior X of the person annoys me, I can ask myself questions like: How does this behavior bother me?, What kind of behavior would I like to see instead from the other person?, How would that help me/ Why is that important to me? How can I discuss this effectively with the other person? By communicating more positively in these types of situations you will make it easier for the other person to respond positively. Thus, the risk of escalation will diminish and the chance of good cooperation will increase.
The second component: being more resistant against negativityThe second way in which communication may be improved is by being more capable to resist your own negative reflexes and to be resistant against the negativity of others. An effective way of responding to negative statements by others is what I call finding the plus behind the minus. You realize that negative statements by others imply that that are annoyed or bothered by something and want something else instead. The emotional way in which they make their point indicates the issue is important for them. Once you realize this you can start trying to understand what is so important for them, why this is so, and what their expectation from you is. When you find this out you can think about whether you can fulfill this expectation. Read more about how this technique works.
A first advantage of searching the plus behind the minus is that it will help you understand better what other people's situation is, what is bothering them, why it is bothering them, what they would like instead, and how this would help them. This technique is also helpful on a process level. As people try to answer the questions you ask them they will most probably calm down too. It is pleasant to be taken seriously and to be able to explain what is important to you.