Fear.

In my case is cultural; to most Argentinians to show emotions is a sign of low upbringing

Why?...fear, which can lead to guilt, shame and much more. Bipedal humanoids are bread to be a collective group, not living alone, we need each other. So people want to have people around them, they want to make those people happy and so maybe they hide their sadness to make sure others around them don't get sad. I can think of many reasons people might hide their true feelings, this is just one.

I was taught, at a very early age, to keep my feelings and emotions to myself. It is a lifelong habit.

One can not control ones emotions. One can only choose to act upon them or not. It is the mature who do this. It is the undeveloped mind that has no self controlling mechanisms. No impulse control. I am vastly more mature than I once was. Challenging myself to grow by choosing what emotions I wish to act upon or not.

When I was younger, during my first real experience of love - I didnt reveal my feelings to my partner - I thought my feelings were obvious -
my computer keeps crashing and I have to start again - frustrating
But she left me as she thought I didnt care - I didnt understand at the time - I thought my feelings were so obvious, but apparently not - so Id advise people not to keep their feelings to themselves to make their feelings known to others - as it can cost you if you don't share your feelings - I still regret my actions even though they were a long long time ago!

Okay.

I hid my emotions because I was made fun of for having them by everyone. I laughed and cried "too much". So, that stopped.

I let my emotions out with words. Used to use actions, get angry. Don't do that any more. Wasted time and energy.

I didn't hide them. I misplaced them, and just like my keys I'm not sure where to look.

It's about trust for many, and often ties in with insecurities of one sort or another, such as fear of rejection or invalidation.

I'm very open and always express my feelings. I don't believe this is always been a good thing. I think I could've developed some very special relationships if I just kept some of my thoughts to myself. I also think people don't express their emotions sometimes out of fear of rejection. I was that way when I was young. When I got older, I just don't care what people think. If I like you I'm going to tell you!

It’s kinda hard for men of my generation to show their feelings. We were still taught that the only acceptable emotions to express is happy or angry. And don’t be to happy. I’m getting better at showing my emotions but it’s not easy. I’m trying not to teach my son to be like that.

If you are dealing with a controlling and manipulative person, the more you eveal your emotions, the the more tools you give that person to play "mind'fuck" games with you.

Certain emotions such as anger are difficult to control, and the loss of control may lead to behavior that is contray to our normal beliefs, compeling us to act irrationally, as in a fit of rage.

1. What is the state of mind of an angry person
2. Why are some people more prone to anger
3. What grounds anger

Aristotle though these categories apply to all emotions and that self control is a virtue which can be taught

Showing feelings and emotions to others is revealing weaknesses. I'm an emotional person because I'm an empath. It's hard for me to shut my emotions off. I can hide them if I'm dealing with a person I don't know very well or I despise.

A person who is emotional is not rational. If a person is not rational, nothing they say or do has any validity. A person who must exprees their emotions is a weak person...anoying to be around.

I hide my emotions only in so much as not wanting to piss you off and make you want to fight. No need for that. I can get my point across and if I do not agree with you I tell you so. I do not shoot guns for recreation to keep my anger inside or control it. I do not hold grudges (real or imagined) against anyone. (Well, wait. Maybe at Trump.) I do not wake up in the night hating Charlie or Susie.
I let my emotions out by just doing normal things that I like. No need to pull legs off insects or kill animals. Nothing hiding inside that wants to shoot adults or school children. I'm not worried that you are "against me" or "planning something" that might involve me. Maybe that's because I do not live in that kind of world.

I am quite a bit older than you and have learned this over the years: live your life with your arms wide open. That is a metaphor for not hiding your feelings, not pretending and not playing a role to get an advantage. As a consequence of this, I am not powerful, not rich, not feared. I am beloved and admired and sleep well at night.

Because people fear being judged,institutionalized and ridiculed. So people will hold in their emotions as a defense mechanism. Best thing for people do is find a network of friends and family that can all come together and help one another with no strings attached.

I have D.I.D I'm pretty immediate with my feelings, but have never grieved for people who died, I wondered if it was coming from an abusive family that made me not care about death -

I'm very emotional.

Let out a good cry everyonce in awhile . Pretending honestly always made me sadder.

Insecurity. they feel insecure so they tend not to let others in for fear they will be harmed.

From my POV have seen people who are repressed because they were forced to "squish" their feelings. Their feelings were invalidated or they were punished for them somehow.
It can start in early childhood. "Don't cry" after a kid bumping their head or getting scared , etc, instead of letting a kid have their feelings and talking them through with them some who aren't equipped or willing to bother would rather just shut the kid up and it carries into adulthood.