The overuse of psychological terminology drives me out of my mind.
It is mental laziness. If you cannot express what you want in direct and simple terms, the chances are that you are talking nonsense.
An example. Instead of:
Why are you projecting your feelings of inferiority onto me? I feel that you do not see me, that you are invalidating my identity.
It is far better to say:
Whenever we go to your family, I have noticed that you only enter the conversation by making a dig at me.
Look at what actually changed between those two sentences, because it is not merely a matter of style.
The first is unanswerable. It makes a claim about the interior of somebody else's mind, to which they have no better access than you do, and it names a permanent characteristic rather than an event. There is nothing for the other person to do with it except deny it or accept a diagnosis. Both of those end the conversation.
The second describes something that happened, at a time and place, which both of you were present for. It can be confirmed, disputed on the facts, explained, or apologised for. It can also, crucially, be changed — because it names a behaviour rather than a nature.
And there is a less flattering point underneath. The technical vocabulary is not usually reached for because it is more precise. It is reached for because it is more powerful: it converts a complaint into a diagnosis, and a diagnosis puts the speaker in the position of the one who understands and the other person in the position of the one who is unwell.
That is a considerable amount of authority to award yourself in the middle of an argument you are a party to.
Say the smaller, duller, more specific thing. It is harder, and it is the only version that has ever changed anybody's behaviour.