Every person has a certain way of carrying himself/herself and behaving in a certain manner
The reason you are sensing these so called “bad vibes” or “good vibes” from certain people, is not because they are literally vibrating these gv waves or bv waves that say they’re a positive or negative person. Not to belittle all these “universe is interconnected” or hippy stuff, but the real reason for this is actually just very simple. What you are describing is actually one of my favorite friends:
INTUITION

We are constantly bombarded with so much information on a daily basis, that if you tried identifying each and every thing that our mind processes. You most probably would go crazy ; our brains are selective in what we want to notice, so as to conserve energy and not overload ourselves of the stress of processing each and every little thing that we notice.
think about it:
the feeling of the clothes on your skin, each and every heart beat, the color of your laptop, the depth of the object in front of you, the buttons on the key board, the next word in a sentence, the random thought just coasting through, the background noise, the sudden twitch of the lips as you said something hurtful, your insecurities, your homework, blinking, breathing, and the list can go on and on…
Our subconscious is responsible for filtering all these mundane data, and gives the conscious mind only 1% of selective data in which you have “choice” of noticing and responding to.
Yes, 99% of everything else that is left is being processed by the subconscious mind. If it didn’t, then you might as well be a Pentium cpu trying to run a game like Fallout or Oblivion on ultra high settings with thousands of mods running.

That being said. The unconscious is very powerful.
During the 1980’s, a Psychologist named John Gottman from the University of Washington, interviewed over 3000 married couples. Each and every couple was videotaped, and was analyzed using a coding system called SPAFF (specific affects). The coding system had each and every category corresponding to all the emotions a couple might be able to express such as disgust, contempt, anger, whining, sadness, neutral, stonewalling, defensiveness and etc.
What John Gottman did was incredible.
He watched EVERY videotape of the interviewed couple and assigned a SPAFF code to every second of the couple’s interaction. Imagine doing that for 2999 more 15 minute videos. Just amazing. Along side the SPAFF coding, they had also used electrodes and sensors on the couple so that for example, When they measured a 10 second video showing the female getting angry, then sad, and then neutral and then suddenly defensive. They would also be able to factor in the ladies’ heart beat rising or that one of them was constantly squirming or moving their feet.
After maybe finishing half or all of the videos (phew finally), John Gottman discovered something amazing. If he now watches a couple for only 15 minutes, he can successfully predict if their marriage will still be intact 15 years later! His colleague Sybil Carrere, discovered that even if they watched a couple for only 3 minutes, the success rate was still impressively accurate!
what happened in the previous story is about a phenomenon of our subconscious mind. This is what Malcolm Gladwell liked to call:
THIN SLICING
this refers to the ability of our unconscious to find patterns in situations and behavior based on very narrow slices of experience.
Our unconscious or “gut” is really good at this. So when you get “good vibes” or “bad vibes” from people, that is your gut being able to tell based from a small amount of experience, that this guy right here is a faker, he’s being manipulative.

This chick? damn she’s so bad vibes I can feel she’s being plastic. I don’t know why but I KNOW. I CAN FEEL I can’t trust her. Yes sir/ma’m that’s your gut or your intuition giving you signals. It’s the same thing as a Moba player, one would be able to “feel” when you’re going to get ganked. Or when you know you’re being lied to, because you’re already experienced at it! no need for your conscious to focus on it, you’re gut is already familiar with it and is saving you the trouble.
I have always trusted my intuition because I know that most of the time, it’s really accurate. I cannot count the amount of times I was able to, upon meeting a certain person tell that “hmm, I don’t like the vibe of this guy, I don’t trust him”. And poof that’s it, I’d follow my intuition and guess what? 9 times out of 10, the person turns out to be a complete dick or asshole.
Our intuition/gut/subconscious is truly powerful, do not underestimate it’s potential. Learn when to listen to your gut. When you feel somethings not right? listen, it probably knows a lot more than you in that current situation. Something YOU might have missed has already been processed by the unconscious. It will save your life quite often and give you the correct answers in life. Too much thinking is bad for us, we get trapped ruminating about a certain thought or idea, only to get tangled by tangents and other parasitic insecurities or memories that we forget to truly listen and take action.
In short? Analysis paralysis.
There you have it. there are no vibes or whatever. Just your plain old gut telling you what is or is not. Once you know about these things one can’t stop feeling in awe of the human being and of its potential.
For example, the rich spoilt brat of a politician in UP, will have a certain trademark behavior and a certain way of conversing, no matter how educated he might get (I ain't stereotyping every politician's son, this is just an example)
If you normally interact with a certain kind of people and if you suddenly meet someone like the one the described above, you will not feel like talking to the person and of the person tries to talk to you, you will try and stay away due to the way he carries himself. That is vibe.
Sorry for that crude answer but that's the best way I could put it in words.
The "vibe" that a person emits, which, if I'm not mistaken, is short for their "vibration," is their emotional sensitivity and benevolence, as I have experienced it. This emotional sensitivity is reflected in what a person does and says, and how they do it. But the degree to which we can get a sense of a person's emotional sensitivity is mostly dependent on the kind of person we are. In order for us to pick up on it, we ourselves must care about the quality of the personality of those whom we associate with. Certain people have bad vibes because they seem selfish, to a degree that would indicate a willingness to dominate or wrong others without hesitation. It would seem that such people could never be your friend, even if they claimed to be. Their lack of emotional maturity and sensitivity makes them a person that you would prefer not to be friends with. At least, that's the way that I see it.
For me, I get them because of past experience with people. Naturally I observe behavior. The way people think, and what they do. I can tell whether or not someone is genuine, or trying to take advantage. I mean, when you think about people you've came across, and your interactions whether good, bad, or indifferent, you get those vibes. At least for me anyway. Hope this made sense... ;)
Well, from my past experiences, the so called "vibes" don't usually exist. However, before whoever that's reading this roll their eyes and down vote, let me explain. It's probably your observation of their behavior and the way they do things. Such as, when some one isn't always a smiley face, and the way they walk is kind of aloof, and they have a low voice, you would probably get a arrogant vibe from them. Or when someone is always hyper, or just likes to smile and talk a lot, you would probably get a "good" vibe from them.
A/N: The first thing people would describe me is that I seem bored and that I seem to look down at people. I don't. It's just that I don't like to talk a lot, and only smile and laugh to my friends. So I don't really trust "vibes". I'll probably talk to them first, and then start to judge their personality.
