Vigil is right about it being due to your perception. If you break people's perceptions down into the fundamentals, there is pessimism on one side and optimism on the other, with realism someplace in the middle of the two; which is kind of how the world really is.
But the way our minds have been taught to filter the events of reality is what makes us come up with the emotions we end up feeling.
I think the way we are brought up by our parents, our genetics, and our environment, all play a role in training us how to think. And the end result is people who see the glass as half full or half empty.
Here is a small part of an article I read just the other day on the subject.
Two identical days, each with the same routine. One goes so well, while the other?
It's a day you'd rather forget. How can this be?
The answer is projection.
On each day the alarm went off at the same time. You snoozed for the same ten minutes and did your morning routine.
But driving to work was different yesterday.
The sun was shining and the constant glare was irritating. Fellow drivers seemed grumpy.
You looked at a few faces to seem them scowling back at you. No-one was letting you in at the intersection, and everyone seemed in a bad mood.
Today however, the sun is shining and it's so uplifting.
Everyone seems smiley and cheerful, even letting you in at the busiest point of the road.
At the lights, you can see a driver next to you obviously singing along to the same song on the radio, and you acknowledge one another with a friendly smile.
So what was different? The difference lies solely within you.
Everything we perceive is our own projection, and playing the 'perception is projection' game can be a great learning experience in self-awareness.
So if everything you perceive is your projection, does that mean you can control your projections?
Of course, and this is where it gets fun. How to do it is to maintain awareness of your state and what you are doing with it both on the inside and the outside.
Maintaining a positive state means that your internal representations of your experiences are positive and this will show, through your physiology and behaviour.
Practice this whenever you are next out walking. You'll notice that you get a lot of friendly nods or smiles as you pass people, purely due to the positive state you are projecting.
You're likely to have had experiences of 'perception is projection' already.
Networking events are a great example - think back to some where you've been really up for it, and it's turned out to be an even better night than you anticipated, where everyone you have talked to has been a great contact and you've got instant rapport with them.
Whereas those events that you haven't really felt like going to have ended with you leaving with either no contacts or none that had any meaning. That's no coincidence.
How does this all work? Out of the two million bits of information that surround us, we only process 134 bps (bits per second).
This means that we can't attend to every bit of information that comes to us. So we really can't see anything other than who we are.
What you see is you and what others see is them.
Practising positive projections can really result in a happy productive day, and gives you control to turn around those days you just want to end.
Ive often found this to be true. The saying about waking up on the wrong side of the bed is all about how if you're in a bad mood and projecting negative thoughts, all the information that your mind filters back to you is negative and it kind of snowballs from there.
The key is to listen to your inner monologue as often as you can, and see what it is saying. Are you always complaining? Are you always positive? Are you somewhere in between?
If you find youre always putting yourself down and expecting the worst in situations, you need to catch yourself when you're giving yourself this negative reinforcement and try to teach yourself to think more positively.
You may actually find that if you go into something with a positive outlook and feel good about it, (just even try and see the smallest good in it to begin with. I find that even just smiling makes me feel better as a start.
) you may find that the experiences you have with others, or the day you have is a "good" day. Compared to the ones where you woke up on the wrong side of the bed.
Having said that, I have to admit its allot easier said than done. Ive been aware of this for years and Ive never been able to completely change my outlook on life, because i find that there are just so many outside stimulae that encourage negative self esteem and negative thoughts. (Just look at Vigil's recent thread, Insecurity.)
But if I ever have children, the first thing I would do is reinforce these concepts of perception in them and try to give them high self esteem in any way I could. Because its better to be taught to think positively from the beginning- than try to go back and fix 20 plus years of negative reinforcement.