Well, in this situation, wherein you do not like anyone calling you ‘dear’ except your father and husband, your anger is justified when some other person crosses the line as per you. But, I believe your fury is only partially justified.
This situation is analogous to the situation wherein you are beating about the bush. If you have so much problem with somebody calling you ‘dear’, then you should either tell that person straightaway that you do not appreciate such frankness in words or you should simply tolerate all this happening. As they say in Hindi, ‘Bhaag lo ya Bhaag lo’, meaning either run away from the situation or participate and let it happen.
Does Not Let You Suffer Mentally- You may make a mountain of a molehill, and this is fatal for a healthy relationship. Thinking in mind all the time is harmful not only to the relationship but also to your health. To stay peacefully in a relationship one has to bring your mind to peace, which is possible by speaking up.
If matters get worse, although you have politely spoken to the respective person about your problem, then close your eyes and understand what's happening. Are they all wrong? Or are you overreacting?
Keeps You Away from Verbal Torture which you think is harassment, but actually, it is not.
Overthinking sucks a lot of energy. So, before mental torture even begins, fix yourself because in the end what matters is how you think and what you think becomes a reality. Sometimes, you have to cooperate and sometimes others adjust and that is how we proceed on our journey of life.