Everyone has his own thoughts which are based on their upbringing and their past experiences. Your thought and experiences are different than my thoughts and experiences. This is the root cause of conflicts arrival. Do not dwell on the past, do not dream of the future, concentrate the mind on the present moment. Thoughts create our mood and our emotions.
So, if we think of something nice we will feel good, but if we think something bad of course we can not expect to feel good, in fact, it is just the opposite. The cause of a bad day has been simply generated by a small episode, maybe even insignificant. A thought attracts another thought, it is like a chain, a bit like the domino effect continues.
Suppose you hate someone, the reason to dislike that person is your bad experiences. If you could realize that attached emotion is bad experience only then you would be able to deal with that. This principle applies to each situation as if you say you love somebody so much. The reason for loving is your good experiences in past with that person. And suppose after marriage, your experiences with the same person is changed with time and it could become bad then you start disliking to that person but if you could understand that these are the experiences and memory only, then conflicts go away from your life, for example whenever you goa for routing with your partner you feel happy, why? because you forget all bad experience related to him/her. So in real life, if you want to be happy always you must forget your past experiences when you start judging someone and see the situation as it is.
A positive thought attracts to positive thought, and a negative thought attracts a negative thought, whether we like it or we do not like it, we believe or do not believe it, that is how it works.
It’s up to us to behave accordingly, decide whether we want to believe and accept it and know how to use this knowledge to our advantage, to live a happy life that we want.