Why do we get upset or feel upset?

Been thinking recently why do we get upset?

I think its one or more of what I am listing below occur.

1. Expectation

It's our human nature, we set expectations, when they aren't met, we feel bad and we get upset. This is a topic by itself, so I am gonna give examples here to make the picture clear and then move on to the next point. We usually set expectations for everything in life, even when we design an electronic circuit, we expect it to work as designed, if it doesn't for any reason, we feel upset. But its nothing compared to the feeling we get from getting unexpected behavior from people we care about.

We usually expect a certain behavior from people who we care about, when something unexpected happens, we get upset, sometimes it reaches to depression. When we care about someone, we think that person is an angel. Specially, when this person cares about you too.

When someone cares about us, we set the expectation of us being the only special person, we expect to get all the care that could ever be given. But this creates so much pressure on the other person. Thus makes both upset.

We have to accept the fact is that people care on different levels, you may care so much more than the person cares.. People have different behaviors, sometimes words betray people and words slip unexpected. and I know the idea of accepting this is just painful and makes us upset.

2. Abilene paradox

Quote from Wikipedia:_ "The Abilene paradox is a paradox in which a group of people collectively decide on a course of action that is counter to the preferences of any of the individuals in the group. It involves a common breakdown of group communication in which each member mistakenly believes that their own preferences are counter to the group's and, therefore, does not raise objections. A common phrase relating to the Abilene paradox is a desire to not "rock the boat"_. " -- Source: http://en.wikipedia.org/wiki/Abilene\_paradox

Group of people could be even two people, we sometimes do things to please the other person or other people, but after sometime, it becomes heavy and we get upset and start pointing fingers.

3. Feeling Lost / Feeling Lonely / Losing someone or something

Sometimes we just feel lost, we don't know what to do, where we want reach with our lives.. This feeling sometimes is caused by unsatisfied expectations. It could be caused by feeling lonely. Feeling lonely is when you miss someone so much and this person is not around. It could be because of losing someone! Its our nature to forget and expect that this person will last for us forever.

4. Fear

Fear is a very important factor, fear from being able to reach the expectation, fear of being lost..  Can't find enough words to finish this part.

At the end, it all related to expectations we set. But there could be a different view, expectations can give hope too.