People do not usually say everything they think about and there are important reasons for that.
That's why it can be helpful to think about the following things before we speak our thoughts:
Is this going to be a hurtful comment?
If it's likely to hurt someone's feelings and it's not important, then it's probably not something that needs to be said.
This might not matter to you, but if you are trying to make friends or get along with co-workers,
it is important to think about whether what you are planning to say is going to be helpful or harmful to the situation.
Is this the right person to talk to?
Sometimes we have something to communicate, but it's not the person
that can help.
Your teacher can't tell you whether or not you have a cavity, that's something to ask your dentist.
Sometimes it's just too much detail and the other person didn't expect that so they lose interest.
This can take a lot of practice but let's say you're telling a story about something that happened to you:
try to limit your speaking to the main/key points of the story instead of telling every detail of the story.
They don't need to know the exact spot you were standing in, and every exact word that you and the other person said unless:
You are telling the police or a detective about something you witnessed.
You are telling your doctor or a nurse about medical problems.