Do you know that your emotions are powerful? They are VERY powerful in a sense that how you feel and what you feel influence your reality.
We are energy beings and we can attract and repel energy depending on how we feel. Our feelings become the point of attraction, the energy field by which all other energies around us react to us.
If you are happy, you are emitting this energy that by law of attraction, would attract like energies into your realm.
In the same manner, when you are not happy, similar energies to that unhappy feeling slowly make their way into your life.
You have heard about karma --- that's how it is.
You have observed that pattern in life of when you start your day bad, it will continue to spiral down the bad route until you switch your 'perception' or the way you feel, and then things start to turn around and go right.
Your EMOTIONS are an indicator of what you are attracting into your experience so use it to guide you to the purpose of your existence --- and that is to live this life happy as you continue to evolve and change.
Some readings for you if you feel like learning more:
With love always.