Positivity is contagious. Being Positive is contagious. Negativity is also contagious. The thing is, it has to be learned through reinforcement. Your behavior can be seen as both positive and negative. The saying "Beauty is in the eye of the beholder" applies to this.
If someone is labeled a positive person, it's not because they have too much positive energy but instead they exude a certain amount of energy that ignores a shitty environment, accepts failure and is someone you internally admire. No one's going to label someone a "positive person" in an already "positive environment", it is expected behavior.
Happiness does not automatically mean positive feelings. It is an expression. Those who search for happiness are drug seekers. Particularly always looking for their next dopamine hit. The chase for "happiness" is never ending. It's for NPCs.
Too much or forced positivity is not positive. Especially if it glosses over negativity. If an environment forces you to be positive at all times, it could reinforce negative attitudes. People who exude fake positive energy are actually easy to detect. If you find yourself in that environment, you are not a culture fit for that environment and you need to accept that.
Some people will express their erratic energy to bombard your senses. I typically assign these people with the psychopath label for that one reason. Why would someone bombard you with energy and they don't know you? They are looking to see which direction you will go in and try to reinforce themselves to that direction to manipulate you. It could be a "positive" direction or "negative" direction. Fact of the matter is that in order to deal with these types, you cannot let them modify your mindset nor your energy.
A public facing position is going to have a mix of negative and positive energy. One day everyone is singing your praises, another day the cursing of your name is shocking and deafening. This is the biggest test of a public figure to see who they really are. Are they steadfast or easily swayed? Do they recoil and reflect the same energy at random audience members? or do they stick with their mindset and listen to the feedback they receive to see how they can improve themselves.
Oh, improving yourself is positive isn't it? The question is how does improving affect behavior. Sometimes people learn to better hide things, delay engagements, redirect attention. They've learned to improve themselves just not in a "positive" manner, but it is positive for themselves. They might show a happy expression or show no emotion in response to their improved behavior.
I tend to wonder, why would you care for exuding positive and negative energy anyway? Because other people exist and you want to manipulate everyone's perception of who you are. You know who you are. If you don't you are lost, easily swayed, have no inherent sense of identity and likely a "go with the flow" type. A lost person will always look to hide who they are because they don't know who they are and it shows through their energy.
You know who also is lost? A beginner when they are starting out in a field that they may or may not be interested in. You can't worry about exuding positive energy and burn energy trying to understand, so right then and there you start to figure out how your body reacts and parts of your identity. You learn to tame it, you learn to redirect energy, you learn how to best perform actions to gain positive results and positive reactions. That gives you positive energy for you to also redirect that energy to someone else.
So stop worrying about exuding positivity or negativity like a psycho would. Psychos will always look to how to manipulate as much as possible, their expressions and energy are always fake.
It is always going to be better for you to exude the energy that is inherent. Sometimes shit is going to go wrong and that'll come out in sighs or rants. That could lead to opportunities to stop, examine your approach and look for alternatives. Sometimes shit goes right then goes wrong, so what same approach, stop examine your approach and look for alternatives. The results give you inherent satisfactory energy that you can express elsewhere. If you know who you are and what defines you, whatever energy you put out for whatever reason will naturally be understood and you don't have to worry about what others will think.