Why do we allow our moods to decide our actions?

We all have both good and bad moods from time to time. That is reality.
In good mood, most of us love ourself or our job or our family very much at one time. However, in bad mood, we sometimes hate ourself or our job or our family.

Have you guys noticed this among yourself?
It seems to me both the contradictory likes and dislikes are purely based on our moods most of the times. Why do we really do that? Is it because we try to justify everything? Is it because we try to categorize between good and bad? Is it because we have trouble in accepting reality?

Why can not we consider just the good and pleasant thoughts and go forward rather than worrying about something doesn't exist?

Why do we have opinion on everything?

Have you people noticed any of the following among ourselves?
>>Finding other religions strange
>>Finding people from other nationalities doing strange stuff
>>Finding some of our work mates very different
>>Even finding our friends sometimes different
>>Finding our loved ones different occasionally

Is this because we try to have opinion on everything? I think we all try to see people with some expectation or have opinion about people who must be compatible to us and who must not. Why don't we agree that the difference between people is a reality? Why do we always expect people around us to be up to our expectation? This even applies to our loved ones.
When we start expecting our loved ones to be something based on our opinions, are we really loving them? Or, is that some sort of possession that we have on them? If we really love someone, don't we love their activities as well. May be not, because as I mentioned earlier each one differs. But why should we allow that feeling of disagreement on something we don't believe in?